Spiderman director Sam Raimi has confirmed there will be AT LEAST a further 3 Spiderman movies. Speaking at a press junket in Los Angeles Rami told us that Sony Pictures have plans to extend the series to six movies - possibly more. Given the current success of the movies it seem inevitable that there would be more. Coming Soon, who reported the story, claims Raimi did however make it clear he had not yet been asked to be involved in the movies.
doesn't want to presume Sony would want him to direct.
Raimi went on to say that he would "find it hard to say goodbye to Spiderman", this to me shows he still has plenty interest in keeping the chair for further next installments. Spiderman 3 will be released on May 4th.