I signed up for Bing Rewards on 12/31/2010, mainly because I was afraid the 250 credits for signing up would disappear come New Year's. I'm glad to say that it is still available and that if you love Amazon as much as I do, you may want to sign up and start earning your way toward Amazon gift codes too!
A $5 Amazon GC is 541 points. The 250 you get when you first sign up puts you just about half way there. The rest of the points I've gotten from checking the offers tab and finding things to click on that credit me with points here or there. I have been typically finding offers of 12 points per action. I don't always see a new offer every day though. However, today there were two offers and that put me over the threshold for being able to claim the $5 Amazon as a reward.
In addition, from now until 1/29, you get 1 point per search. This adds up quickly too and though I may not search there every day, I'm still managing to accrue points easily.
You do need IE to install the Bing Bar. I use a different browser for most of my searches and do have Bing installed on my IE and do my best to pop on to the internet through IE too. The confirmation email stated that subject to verification, I should get my reward within a week or two.
If you haven't signed up, you can go here to do so. This is not a referral link.