Freeroll Online Poker Tournaments
Pokerroom have freerolls with $300 payouts - one of the biggest in the industry
PacificPoker have about 10 freerolls every day
AbsolutePoker have about 15 freerolls every day
PokerStars have freerolls that give tickets to a weekly $1000 prize money tournament
Freeroll Poker Tournament Strategy
A common strategy you will see in freerolls is extremely wild play in an effort to build up a large chip count early on. This is a high risk, all or nothing style strategy. When it pays off, it's hugely enjoyable, but does mean that you will go out early in most tournaments.
A strategy which will get you through to the money more often is to play a tighter game, however this will not often get you through to the final stages of a freeroll, as some of those reckless players will have survived, and their chip counts will be so high as to be almost unassailable.