Welcome!
let's see...
America West - 6,000
Continental - 22,600 (CO)
US Airways - 8,500
United Airlines - 1,500 (UAL)
you can bring CO up to 25k for one RT domestic award ticket thru using idine or other services or offers avail all over the place in this and the forums like it online.
you can also, as mentioned earlier, deposit these into an AMTRAK acct but at the 5000 per rate. you could then transfer these to United but call amtrak first about this and no, you cannot go the other way. Number on their site:
http://www.amtrakguestrewards.com/
Then you would have nearly enough on United to do some activity and bring THAT acct up to award level (25k or so)
Idine, in case you have no idea, lets you assign any credit or debit card--regardless of whether it is a miles card or not--to any airline and when you go eat at tons of places all over the US, they give you 10 miles per dollar tax and tip included.
www.idine.com will tell you more. They have other offers but we like the miles one. Miles take 4-6 weeks to hit your acct but to bring one up to level it is a great thing indeed.
you can also use those UAL miles to get some magazine subscription... Check out the offers for magazines4miles on
http://www.milepoint.com
some airlines have numbers you can call to do it without the web and sometimes these allow for less miles and faster service. I cant find the list but you know, Pgary's site has everything and I know it is in there probably in the shopping section.
http://home.earthlink.net/~pgary/MilesFrame.html
everything depends on how you wish to use things: one might use the UAL miles to get a magazine, and keep the CO miles and try to later have enough to get a free RT ticket. OR, one might transfer those CO miles thru AMTRAK into UAL and use THAT to get a free ticket which, by the way, can help you in yet another way:
US Air is a partner so if you fly them, that program's miles will grow for you too. Why not get into flying on United and US air and make those two grow the most?
America West... I have no idea. They use dto be CO partners but no more.
Hope some of this babble helps you choose. think long term and remember: as long as you keep them active they will never expire!

MM