Yeah, just find an old Fuji or something and convert it.

Some helpful links:

• Fixed Gear on the Cheap
• Sheldon Brown
• Sheldon on fixed gear conversions which is prob what you want. Here he talks about what kind of bikes to look for: should be very helpful.
• If you want to go the easy way get an old bike and throw on a fixed rear wheel. For that I would check out IRO cycles.

If you have some fixed specific questions it might be better to do some searches on the Fixed Gear and SS forum.