Ok, it looks like I've told this wrong (many, many times). I had it that he used the symbol to get out of a recording contract, but thats not quite right. Heres the story from an article i stumbled onto:

"In 1993, Prince’s dissatisfaction with his record label, Warner Bros., finally reached its peak. Despite his superstar status and $100 million contract, the Purple One didn’t feel he had enough creative control over his music. So 'in protest,' Prince announced that Prince would never perform for Warner Bros. again - this unpronounceable symbol would instead.

The symbol for the Artist Formerly Known as Prince combined three ancient symbols: the male symbol, the female symbol, and the alchemy symbol for soapstone, which was supposed to reflect his artistic genius. Prince retired the symbol when his contract with Warner Bros. ran out in 2000. Today, he is again Prince."

just slightly wrong, but i thought that I could straighten things out here. and yes, I am a fan.