In reply to Frank4short:
> Best time of year to visit?
Spring or autumn. People do go between November and Feb since many of the best climbs are south facing, but the nights are bitterly cold and weather can be hit and miss - you don't want to fly all the way from UK and lose 3 days to a snowstorm.
> Is it easy to get to?
You'll need a car. The closest international airports are Denver (about 6 hours) and Salt Lake City (3.5 - 4 hours?). Denver might be cheaper flight though since it's a hub for several airlines, I don't know about SLC. Another attraction of flying to Denver is that you can stock up on decent beer in Colorado before hitting Utah's liquor laws. It's also possible to fly from SLC to the nearest town, Moab, but I don't know how much that would cost. Indian Creek is about a 40 min drive from Moab, so you'll still want to camp at the Creek itself.
> How well do you have to be able to climb to even consider it?
There's very little below 5.10. The climbing style is physical and sustained more than technical - Colorado climbers tend to find the grades hard, Californians find them easy, probably because there are more cracks in Cal. Don't get too hung up on grades though, it's really hand size dependent. It's pretty common for those with small hands, women especially, to find the 5.10s desperate and the 5.11s much easier. Whatever you do, don't expect to climb more than 3 days in a row if you're very fit.
You will need a big rack of cams, though. wires are for the most part useless, and it's not uncommon to use 6-7 cams of the same size on a route. Lots of people go there in large groups and pool gear for this very reason. When I was there we scrounged between four of us about a dozen sets of camalots, which isn't unusual. The placements are excellent, and with sufficient gear it's really like sport climbing with cams, so lots of people feel comofortable pushing themselves there.
If you plan to invest in some cams, BD C4s are ideal for the Creek - buy them in the US rather than the UK since as I'm sure you're aware they're a fraction of the price. For the 5.10 climbs lots of #2 and #3 camalots. For the 11s 0.5 - 0.75s (this is just a general rule of thumb though).
For days off, the Arches National Park is pretty much a must-see. Also, you might like to consider doing one of the Castleton Tower routes whilst you'r in the area (see www.mountainproject.com foir nore info)