Let's just have one general discussion thread for ME3.
I assume that if you read this thread, you have played ME1 as well as ME2 and no spoilers will be marked for these games. However, for ME3 I'd like everyone to mark spoilers and/or white them out.
First, even if you are non-American (or from any other country that it has already unlocked), you can play it now if you unlock it with a proxy (as seen here, link provided by Silver in the WIT). The first one didn't function but the second proxy worked just fine. After you activate the game, make sure to disable the proxy again, since it's a potential security risk. Starting up ME3 without the proxy worked and without causing any trouble.
Second, if you import a character created in ME1 and didn't change the appearance in ME2, ME3 won't be able to use it and you have to make a new face. You can still use a face code, however. A bit of an obvious problem to have in the game but apparently Bioware are working on this.
Additionally, here is a link and tutorial for Gibbed's ME2 save game editor, which allows you to change most decisions made in the previous games.