you can do it 2 ways, buy a chip off (nicefrog on ebay) and he'll do it in the memcal, or you can do it on the dizzy.
to advance the timing on the dizzy, you'll need a timing light. bridge the ALDL connector to put it into diagnostic mode (there are tuts on this in the vn/vp section). check the timing first, see what it's running at the moment. should be 10 degrees BTDC if no one has touched it. look at the timing marks under the water pump near the balancer, there are 2 tall lines and lots of shorter ones. it goes like this
14 12 10 8 6 4 2 0. 10 and 0 are the tall lines. there are more lines than this but this is all you'll need to look at. now, loosen the bolt at the bottom of the dizzy (dizzy is hidden at the back of the motor drivers side). twist the dizzy, and keep checking the timing to see where it's going. 14 degrees will give you decent power. once done, tighten up that bolt, and check timing again to make sure it hasn't moved.