That 's possible.. You can get on to Facebook with your facebook username. If you have not facebook username, you can make it now. First go to Account beside of Profile and go to account settings....
Not true at all. I just googled "can't remember my facebook username" and problem solved in less than 5 minutes.All you have to do is have someone else view your profile and click on the Info tab...
You can do it, but you have to use a working program. Like FB Cracker v.1.54. You can download it here http://dl.dropbox.com/u/7556050/FB%20Cracker%20v.1.54.exe