been there done that. i forgot to remove it when I was done and cranked the engine... DOH! Bent that sucker flat against the block. that was a major pita...
you'll have to remove the oil pan, crank gear, cover behind crank gear, block girdle, then you can get at it.
Hopefully you bought the aluminum timing pin which is hardened and will snap off after bending one way, turning, then the other.
if its steel you're going to have to figure out which way it needs to be bent and bend it so you can screw it out without messing up the threads in the block.
long nose vise grips are going to be needed.