lemme see if I have it right.
If you put your foot on the clutch, and put it in gear, and then let out the clutch, nothing happens?
Does the clutch feel normal when depressing it?
its gotta be disengaging, or you couldn't put it in gear.
It DOES actually go into gear right? Not just the shifter handle moving? Cause if the cable(s) have come off one of the levers etc, you could get these symptoms. YOu'd push the lever into what would be first gear and let out the clutch, but it will still actually be in neutral.
Also this could happen if the lever arm came off the stud that attaches it to the internal parts of the tranny that shift it.
Have someone put it into gear(engine off is ok) and watch the lever on top of the tranny to make sure its actually in gear. The lever(if you don't know) is located on the top of the tranny, near the front, at the passenger side of the engine. Its behind the air inlet. If you have a 1g turbo anyways. if its n/t, same location, but the air inlet shouldn't be blocking it.