Same here. I use it and if I come across a site that doesn't have a login, I create one, give it my spam addy, and then add it to bugmenot.
There is an awesome extension for firefox (assuming this is the way you found it anyway) that you just right click and there is a bugmenot option to fill in the login form.
Good stuff!
//edit: I need to read, the origional post mentioned the extension
I need to goto bed!