Gift the kimono? These things are a commitment, and not a cheap one at that. You need a bewildering amount of accessories to pull one of these off. And there's so much protocol to learn about which ones are appropriate to your age, marital status and the occasion.
I'm still trying to learn and digest information about them so here's a thread for anyone interested in acquiring/gifting/wearing traditional Japanese garb.
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Faux Yukata
If you like the cotton dressing gowns offered at many Japanese hotels then these make easy souvenirs - but they aren't traditional yukata, although the fabric might be printed with traditional yukata patterns. An easy buy, they can be found in departments in a range of sizes - the length (shoulder to, hopefully, ankle) is shown on the packets in cms. (See 'nemaki' described in post 2, which would make a good alternative)
Children's Jinbei 甚平
These are adorable alternatives to yukata and very easy for children to wear -
LINK SHOWS RANGE OF TYPES. Folds at the shoulder can be unpicked so the child has a few months extra wear out of the garment.
I tend to buy these second hand as presents - but have started getting these on ebay as the postage costs to the UK are more or less the same as a return ride on the local train in Tokyo.
Here's a recommended source
Adults jinbei are also available -
these aren't quite so adorable 
but are still an easy purchase if you like them.
Kimono as dressing gowns?
If you have the fantasy of wrapping yourself up in silk with lengths of gossamer material dripping from your arms (and who doesn't?), you're probably best off not getting a kimono but a kimono petticoat - a
Nagajuban (or juban). The collars can easily be replaced (these are called han eri) so if you find a gorgeous second hand one, perfect except for an age stained collar just replace it.
New or old, they come in a huge array of colours, patterns and textures - some of the most beautiful are artfully died using the shibori method. As they don't get folded over your belly in the same way as an outer kimono does they are shorter, which is why they are ideal as dressing gowns - you shouldn't trip over them. Nagajubans come with long sleeves in various lengths (for single women's long sleeved kimono - called 'furisode') or with shorter sleeves. If you are thinking of using it as kimono underwear make sure the width isn't wider than your intended kimono.
Yukata
If you
do want to try your hand at wearing Japanese clothes - this is probably the set of items to start with.
you'll need:
* I personally recommend knickers with an open gusset (so you don't have to pull them down).
These are good if like me you don't have a washboard stomach.
*A set of comfortable underwear so most of the yukata isn't directly on your skin - a hadajuban and susoyake set is best - I like the cotton gauze kind.
*The Yukata itself - ideally as tall as you are but no less than 10 cms shorter than your total height (nor more than 10 cms longer). But the further from your height the yukata is the harder it is to put on and wear as it makes getting the mid-section fold right difficult (worse case scenario is a 2cm fold around your upper hips which is what I need to do to wear a 148cm yukata I've been given - I'm 164cms tall. Yukatas without the fold look like pyjamas)
*A Hanhaba Obi - this is half the width of a traditional kimono obi belt.
*A couple of Date-jime ties - mens ties will do if you can't get these - I recommed buying a "hakata obi" which is an 'underwear belt' worn under the outer Hanhaba Obi.
Some people like to wear a stiff obi ita under their belts too - this is almost like fixing a washboard to your stomach and helps with any lumps. Just tuck it into your obi before you start tightening it.
Here are two segments from the Aoyama Kimono Gakuin
Yukata DVD someone was kind enough to uplaod onto youtube. I now own these DVDs and they are excellent.
HOW TO PUT ON A YUKATA
HOW TO TIE A YUKATA (Hanhaba) OBI (note that the model is already wearing a hakata obi)
It may be in Japanese but it's ten times clearer than any English book I have or instructional drawings/photos I've seen. Just followed the instructions myself and picked up some more hints - the elasticated clips shown are also worth getting - on my packet they are called kimono beruto (belt) in katakana.
This is what I'd recommend getting for a little girl who is too old for a jinbei. There are some beautiful yukatas available for children (some with very long sleeves) and hanhaba obis are also available in children's sizes. As little girls usually have the ideal tube like body for a yukata, the children's obis are often softer.
A Haori jacket
IMO More than the other options (apart from the jinbei) these potentially make the best gifts. Although they come in a range of lengths, they are usually about 75cms long, so cover your bum, and have flapping kimono sleeves. Designed to be worn over a kimono they come in wide range of colours and a vast array of patterns and textures (including plain black ones, with or without family crests). The haori style is usually much more flattering than the closed Michiyuki style of jacket.
They don't fasten so can be left open or are secured at the front with haori chords (which can be bought seperately - this allows you to change the colours depending on what you're wearing it with). Some are very refined and can be teamed with trousers for evening wear - unfortunately, larger busted ladies can look quite frumpy in them (my mother looks awful in these whereas my sister-in-law looks fantastic).
Check the overall width to make sure they aren't too short for your taste (along your arms I mean).
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And that was the easy bit!
I'll leave this for now and tackle kimonos and furisodes later
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For men?
I know even less about traditional men's dress - this seems to be a very good video of how to dress and what's involved:
http://www.youtube.com/watch?v=Ic7O0FxVZV8
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AVOID
Synthetic silky garments of the kind sold in the airports or which profilerate in Ebay from sellers in China (
like this)
