Royal Vegas Poker ran a one-off freeroll on February 4th 2006. This was the first real biggie of the New Year and the prize fund was a fantastic $15,000! 

Purple Lounge is an up and coming new poker site that are offering some amazing bonuses. Listen to this - 100% match up bonus on your first deposit up to $1000!. This is the biggest one I know of on the internet and it's an awful lot of free poker! 
Purple Lounge also give you a more modest but no-strings-attached $3 just for signing up, not a fortune perhaps but equivalent to a lower placed prize in some of the freerolls! Click here for more information about Poker Lounge

Noble Poker announced what they claim is the single biggest prize ever in the history of sport!  Quite a boast but $100 million would take a bit of a beating I think.
The amazing thing about it is that the tournament is a FREEROLL! Now whilst the prize of $100 million is unlikely to be paid out (you need a royal flush in spades to win it!), Noble poker are heavily insured for the prize so that if the event did occur, they WOULD pay out There are other prizes too of course for this mega event so please take a look at the site.
Details of three daily freerolls at Noble poker are below, the prizes are a bit more modest at $100 but still worth entering. Click here for more information about Noble Poker

32Red Poker had a big $2006 New Year freeroll on Jan 2nd.
Note that at 32Red Poker you need to use the Log-In name that they issue you to log in with, not your screen alias like you would use in most poker rooms. Click here to go to 32Red Poker.

Inter Poker had a massive $5000 freeroll on Dec 23rd - Hope you made it! It was a biggie but with only 1000 places available you had to be quick.