VERY rough body equivalents between Nikon and Canon... Some bodies don't exactly match as well (D200 vs 5D) as others (D80 vs 30D), but you can get the general idea...
(Nikon body) ~ (Canon body)
D1/D2/D3 ~ 1D/1D2/1D3
D80 ~ 30D
D70 ~ 20D
D50/D40 ~ 350D/400D
D200 ~ 5D
Boo on Nikon and Canon for having the letter D in every one of their model names...nevermind the fact that "D" probably stands for "digital!" Kinda funny to see how Nikon can't name any cameras "D60" or "D30" because those were both early Canon DSLRs.