it's potty time!

For better or for worse, Mr. has shown a strong interest in using the potty in the past week or so. I'm feeling grossly unprepared for this -- I'm not even quite sure how to urge him along. I haven't made the decisions like sitting versus standing, potty seat on the big potty versus the little training potty. So far, he makes the call when he wants to try (consistently 1-2 times per day), which potty he wants to use, and how he wants to use it. I don't even know whether to keep on letting him pick everything, or try to "force" it by sitting him down on it at times I know he is likely to go. Regardless, his attempts have been consistent and consistently successful. He can stand or sit, and goes number 1 and number 2 in both sizes potty. He has even gone at school 2 days in a row. We even celebrated last week by going out and getting big boy (Elmo) underpants (that I haven't been brave enough to try yet). I think this is all good, right? Any suggestions out there for potty training? Especially boys?