Bodog has a daily 500 dollar one at 9:40, but i've never placed.
Absolute has them ALL the time, just won a whole $3 last night (second finish itm), but beware as you have to go allin all the time and the last hour the blinds get so high that everyone is short-stacked. (think 40,000 blinds avg player has 324,000) so its hard to place unless you got guts.
Fulltilts are good, but fill up fast. So be prepared to register on the hour. (i.e at 9 on the dot for a 9:40 freeroll)
PokerStars has the most but are the hardest (imo). They give you a ticket to a larger tourney (cool) but you have to go through 11,000 people to get it. The closest I have come is in 100 (top 99 get tickets) sigh!
As a bonus though, they have Razz, stud and omaha freerolls.
IMO stay way from UB because I have won two of them. Now I have 3,000 points but I need 5,000 to cash out my points and 200 bonus dollars which are only useful if I have money in UB. So they don't pay in cash. They pay in UB points or bonus dollars.
Cake Poker is an ok one.
Carbon is also ok. Try their badugi freeroll. Such relaxing fun!
Hopes this helps
GL on the felt