...any ideas?

I have a eos 20d canon
28-135 lens
70-200 lens

and I need a wide angle one

is this an old model?
is there anything new suitable for the eos 20d?

anyone has it?
I'm shooting mostly indoor (lots of people standing side by side with a wall behind me :-) )

According to many reviews it is an excellent lens :)
The only "problem" is it works only on APS-C slr (Canon 300D, 350D, 400D, 20 and 30D). If you upgrade to a full frame sensor slr like the Canon 5D, it is not compatible.

You have some reviews about it at
http://www.photozone.de/8Reviews/lenses/canon_1022_3545/index.htm
http://www.fredmiranda.com/reviews/showproduct.php?product=221&sort=7&cat=27&page=3
http://www.luminous-landscape.com/reviews/lenses/Canon-10-22mm-test.shtml

For the 20D, it is the best ultra wide angle available.
If you only need a "normal" wide angle, there is also the Canon 16-35mm f/2.8L which is must faster at f2.8 (good for indoor photos). It can be used later on full frame sensor if you upgrade your slr to the 5D. It costs a lot more than the 10-20 but it is a L lens.

I'm checking prices now... but if there is similar price difference as in the f4 and f2.8 70-200 lenses... well... :) maybe the f4 will do! ha ha