Since you didn't indicate you'd already seen it, here's the same question twice (with some useful answers) on SO:<p><a href="http://stackoverflow.com/questions/2627387/is-there-a-decent-alternative-to-yahoo-pipes" rel="nofollow">http://stackoverflow.com/questions/2627387/is-there-a-decent...</a><p><a href="http://stackoverflow.com/questions/2019887/alternatives-to-yahoo-pipes" rel="nofollow">http://stackoverflow.com/questions/2019887/alternatives-to-y...</a><p>Personally, I think pipe2py looks interesting.
This works ok:
<a href="http://open.dapper.net/developers/webservices/search.php" rel="nofollow">http://open.dapper.net/developers/webservices/search.php</a><p>If you're talking straight rss feeds, its probably just easier to write it in code. But Yahoo Pipes is more a GUI tool than a coding solution, so I'm making the assumption you don't want to code this yourself. In that case, check out Dapper or Kapow! Technologies. There are others, but those are probably the best.