According to Wil Wheaton’s web site, Wesley Crusher will be on UPN’s Enterprise as a reoccurring character.
His website says there are technical difficulties due to the announcement, so there is a tempory page up. At the time of this writing, the temporary page has the details. There was a letter writing campaign to get Wesley back. Fortunately, he will not be saving the Enterprise each time he says. Also, he will be written as a darker character (yay). I am sorta excited about this provided they handle it well.