Based on the model number of the drive, that seems to be a last gen TiBook, making it the 1GHz model. And, it does indeed sound dead. You can certainly replace the drive yourself if you like. There are a number of third party laptop superdrives available, and the TiBook is actually a pretty simple one to take apart. If you're squeamish about opening up your baby, however, it would be best to have a dealer do the install.
Occasionally, a small piece of felt that is present in the opening of these drives starts to peel up, preventing discs from being taken in properly. If this is the case, just cut away the felt piece. Also bear in mind that TiBooks have strange drive caddies in which the optical drive sits. As such, you may need to do a bit of fiddling to make a third party drive fit.