Maybe this is old hat to soem of you but this is the first page I saw where I could compare the various smartphone offerings from various carroiers all on one page:

http://www.myrateplan.com/keyboard_phones/

Notables.

Cingular 7100g / 7290 Free
T-Mobile 7290 $99
Sprint 650 $149
Cingular 650 $199
Verizon 650 $199
Verizon 700w $299

You can compare features of up to 10 phones even tho there are some notable errors....battery life of GSM and CDMA models listed as same Should be 7.5 and 5.0 hours).....Sprint / Cingular models listed as 40% heavier than Verizon.....few other things but over all quite usefull.