I've never used a frame set in my life, and wouldn't even know where to start currently. I wouldn't even be considering using one now, except I have a simple solution to a problem I have.
Basically, I want to play a single track of music and have it playing the background for my site. The catch is, I want it to play uninterupted when I switch windows.
I thought a solution might be to have an invisible frame right at the bottom of my template, where I embed the music, or put a little flash music player.
Of course I'm rather concerned though that this will make my site unindexable with search engines. I understand this is the reason people don't use them, and it makes sense. But can I get away with this? Bare in mind I know nothing about frame set. :)
I've successfully used framesets over the years. The major search engines don't seem to have any problems. I also keep a noframes version as well. Done correctly there should be no problems. I will caution about having music running in the background. Most visitors will immediately hit the back button and never return.