I think there is probably a writeup in the Tech Section on this. Removing the timing cover also involves removing the front crankshaft pulley (damper) and the oil pan. If the leak is only from the crankshaft seal, it is possible to change it without removing the timing cover.
Bushing: Sometimes there is a groove worn in the pulley shaft that causes even a new seal to leak. There is a thin sleeve that you can buy, that slips over the outside of the pulley shaft to cover up the groove and provide a good surface for the seal to ride on.
