Any suggestions for a guide/driver from Yogyakarta to Borobudur?

1) Most Convenient and Most Expensive way: have your hotel book a driver. I wouldn't bother with a "guide"--you can do just as well with a little pre-reading in your own guidebook, or pick up a guide for about Rph 40,000 at the Borobudur entry route. All the Yogya area drivers know the way out there and back and I'm not sure shopping around for a "perfect" one is going to be of much use. I was in Yogya in February and seem to remember hotels wanting US$ 50-70 for this trip, done on a 1/2 day basis. I think this excludes the Borobudur entry fee itself, but inquire.

2) Slightly less convenient and less expensive way: head to the main drag in Yogya (Jalan Malioboro) and bargain around with a taxi or private car. Should be able to get for 25-40% less on transport cost than hotel rates, depending on your bargaining skills and tourist numbers (or lack thereof) in Yogya at the time. Make sure driver understands fuel is on him, and what total time frame will be.

3) Cheapest way: Taxi to Yogya Jombor bus station, public bus to Borobudur village then becak or long walk to entry gate. Same way return. Total cost, about US $6-7 + entry fee. Public bus is not a/c, not luxury, but "colorful" and not bad for trip about 1 hr each way. For those of you with DIY independent travel experience in developing countries, it's pretty tame. Is about 15 minutes slower than a private car due to stops. This page has a very good how-to with costs--scroll down to the Candi Borobudur subsection.

You didn't say whether you are doing a day trip or an overnight. IMO, Borobudur is best in the very early morning hours, at sunrise. The best way to catch this is an overnight in Borobudur village, which now has a variety of accommodation in all price ranges. I stayed at the Manohara, which is overpriced for what you get, but is right on the grounds of the Park at the base of the monument and has its own back gate in, bypassing the regular tourist entry gate. Advantage to staying here is having (a) free access to get the monument after 3:30 or 4:00 pm and especially (b) access for Rph 150,000 to the special "Sunrise Tour" which allows you access between 4 and 6 am. The park doesn't open to regular non-Manohara visitors until after that.

On my trip, I arrived at the Manohara from Yogya by method (c) about 3 pm one afternoon, went up on the monument for free until closing time (5 pm), then up early for the sunrise tour, back for breakfast and a nap, then left at 11:00 am for bus back to Yogya.

Warning: Borobudur gets unbearably hot between about 9 am and 3 pm unless it is raining, so if your visit is during that time, come prepared with lots of water, sunscreen and hat. Unlike Bagan (Myanmar) or Angkor (Cambodia) sites, there is no shaded relief in which to seek refuge.

I'll second both staying at the Manohara and taking the tour -- the one hour you have the monument to yourselves makes a huge difference. After it's gone, the tour groups and schoolkids start marching in and the temperature ratches up.

Also, while Borobodur is a very large structure, unlike eg. Angkor there's only one of them and only one way to tour it: start at the top for sunrise, then work your way down in spirals. Unless you get a guide to try to explain the reliefs etc, you don't really need more than about two hours for even a very leisurely circuit.