Karma - 12:29 pm on Aug 24, 2011 (gmt 0)
I like to think that, these days, Google knows what is and what isn't an affiliate link by using the data they collect from Google search-bar and Chrome. I don't think a redirect will make any difference.
Opinion seems to be split about how to best deal with affiliate links. I think it'd be better to just nofollow them.
<a href="affiliatelink.php" rel="nofollow">blue widgets</a>