It's free, and can be really-really-really hands off, a small initial bit of interest and then nothing more for the rest of the season, or adjusting your team every week like some of these schmoes.
Click the link jim gave a couple pages back... you will need to register for a username at nfl.com (this is the one moderate-pain-in-the-ass part.) Once you have a username, just type in your team name, and you can be done if you want. Or you can click the link to rank the players you want for the draft, with a handy little drag-and-drop list interface. If you don't touch it, you get the website's default ranking of who they think is the best. That's it. The draft happens, you get who you get, then it posts everyone's scores and rankings to the website each week. Trade players, or ignore it, it doesn't matter.
It's nice if you put the occasional effort towards smack-talking in this thread during the season, though.