The LA Times is reporting that Spider-Man producer Laura Ziskin wants Spider-Man 4 for May 2011 release date. Still no word if Sam Rami or Tobey Maguire will return but Sam Rami has expressed an interest to return to the series so I am sure if he is directing the cast will return.
Also Sony has paid Marvel to renew its rights so I doubt Spider-Man will feature in the Avengers or cameo in any other Marvel Studio film.