IGN has the first interview about Spiderman 3 for the Wii.  It is a lengthy interview and provides lots of details on how the game is played and what to expect from the storyline.  Here are some gameplay details from the interview:

IGN: How ridiculous will I look playing this game in my living room?

Mintz: That’s up to you! If you want to put on your Spider-Man pajamas and flail your arms around to sling webs just like your hero, be our guest. If you’d rather sit on your couch and swing around the city with gentle flicks of your wrists, you can do that too.

Can’t wait!  This is just what the Wii was designed for—flailing about in one’s pajamas

Source: IGN Wii