CAE's bridge program is good, reasonably affordable, and you do the airline interview BEFORE you start the program, so you know you have a class date when you start. Right now, it's limited to Pinnacle only, but it beats plunking down some large coin at ATP and never getting a job out of it.

Jet U - some people I know went there. Over-priced, too long, but it gets people jobs.
Flight Safety - good, but way too pricey
Regional Airline Academy - don't hear too many good things about them
Gulfstream - don't even think about it