wide angle lens for 20d

i will be shooting a wedding in july with about 18 brides maid any sugg on wide angle lens to use with this camera thanks angie

wide angle enough with some good range, 16-35 f/2.8L (will be good for portraits.)

if it's outside, 17-40 f/4L

otherwise, for SUPER wide angle, EF-S 10-22mm f/3.5-4.5

If you need to keep it somewhat under $400 look at the Tokina 17mm. If price be damned look at Canon's 16-35mm.