As it stands the ISPs are:
TSTT
Carib-link
Caribel
FLow
Illuminat
Lisa Communications
Those are the prominent as best I know. TSTT is the largest (duh) catering to residential via dial-up and DSL, corporate via EV-DO, DSL, Lease circuits (T1, ISDN, Frame, etc). Flow is area sensitive atm since they only offering internet to certain part of the country, otherwise their services are more leased circuit type for interconnectivity of offices. Carib-link has dial-up and another high speed service.. not sure what though, Illuminat deals with corporate users only and via wireless. Caribel and Lisa are bout the same, wireless as well. Then there's Greendot... its' wireless but there have been alot of bad experiences with them... however they are the only residential wireless available really... so those are your choices sad to say.... DSL, dial up or greendot...