Lets start with this oldie. Luckily, frames are becoming a way of the past what with the use of DIV layers and the slow onset of incredibly flexible AJAX coding. The long and the short of it is that if you have Frames on your website then you are starting off at a disadvantaged position that cannot be truly search engine friendly no matter what you do.

There are, however, some remedial fixes that will tie you over until you can redesign your site; yes I said redesign. The fix that I recommend is to use a noframes tag whereby you place another version of your web page inside of your framed page. This 'backup' page is what the search engines will view; here you can place relevant content and navigational elements so that the search engines can at least navigate portions of your site that are (hopefully) not framed. More info on the no frames tags.

More info on the no frames tags.