Placing a registration form on FrontPage

Hi, i’m new on WPMU but i have some time working on my sites with wordpress and i love it. However, i’m starting a new personal project and one feature i wanna offer to my users is the possibility to register right on frontpage, without having to go to ANY other section. Does anyone can gimme a hand with that?

And i have to ask for one more thing, how can i place a login bar right on the top of my site, like edublogs?

Thanks a lot for any help you can provide me.