You stick to your lyrics. I've been in nashville now for almost twenty years and there are plenty of guys around who do nothing but write lyrics. My buddy Jim Brown had some nice music lyring around until his friend Don Rollins showed him some lyrics titled "Five O'Clock Somewhere." Now he's got a number one song.
I think the pendulum is actually swinging away from the purely singer-songwriter thing. There are more big-time artists who are "created" by producers who write or work with teams of writers. The producer is becoming the star again.
I post my lyrics and have clips of my songs on my website www.phoebeclaire.com
As long as you have them copyrighted, you shouldn't have any problems with theft. And anyhow, the good writers are good enough to steal your stuff and not violate the copyright so you might as well get your stuff out anyway.
I've got a song about the Sgt. Pepper Album cover on my website now. Also "I Saw John Kennedy Today" which is getting alot of downloads. I've got a song about Pete Best that I need to demo up properly.
Anyhow the internet is a great place to try material out. See what flies and what doesn't.
P.S. as far as lyricists go, Robert Hunter (Grateful Dead) is a good model. He collaborated with Jerry and company on their most classic songs.