how can i serve with spin

I think the single best advice for learning to serve with spin is to WATCH other people serve.  This includes opponents.  Next time you play against someone who has a really difficult serve, watch them and see if you can learn something that you can use yourself.  Who knows, maybe you can give them a taste of their own medicine!  Similarly, watch youtube videos of professionals serving.  Slow motion from multiple angles is REALLY helpful in this regard, and that's where instructional DVDs like Pingskills Secrets of Serve really come into their own.  Main thing though is to watch LOTS and LOTS of different styles and techniques.  Learning to serve in table tennis is one of the most enjoyable and challenging aspects of the sport - plus it's also something you can practice with or without an opponent.