Is my Baseball card worth anything?

I have an old, old, I'm talking old baseball card of Ken Griffey, Sr., from when he played for the Reds. Is there a site I can go to to look up if it's worth anything? It's an old Topps card from when he was drafted in June of 1969. Any info would be great! I also have Barry Larkin, Mark McGwire and some old ones of Nolan Ryan. Thanks!