Frames, Sessions & Search Engines

Hi there, I have a question about how Search Engines handle sessions and frames. Since my site uses frames, and i think search engines link to pages individualy and not the frameset, i wanted to use sessions to indicate if a user comes from a search engine (then it doesn't have a valid session) and if so just redirect the user to the main page. But i'm afraid that search engines will get redirected to the main page everytime it try's to index a page. What do you all think, and might there be another solution? Thanks, Jeroen Geusebroek P.S. Please CC me in your reply, i'm not a member of the list.