Good things:
its only $10;
its a 17mb client you download, because everything is streamed off servers.;
lots of fun;
low lag;
BAD things:
you MUST have broadband to play;
scripting objects can be hard if you dont know anything about scripting languages;
driving isn't always too good.
if you want to own "virtual" land, then its a monthly fee, depending on how much you own.
the link is: http://www.secondlife.com
Things ive done since late March: built boats, started a drag racing association with a friend, crashed a "wedding"(i started sniping before i realized it was a wedding

P.S.