Rigging a keyboard to autofire?

[Moniker]

I was going to post this in hardware, but I guess it's more of a software question.

I prefer using keyboards for shmupping, so I'd like to assign a key on my keyboard for autofire (to play ChoRenSha, eg, without button mashing). So for example, I'd like to make L-SHIFT act as an autofire trigger for the Z key.

I haven't been able to figure out how to do this, but there must be some way to do it with gamepad software or the like. Using Xpadder I can make a gamepad button spam any keyboard key; I'd just need some way of triggering the behavior without actually using a gamepad. I'm thinking that if MAME uses keyboards to emulate arcade sticks, there must be something out there for more general purpose use.

Anyone know of any utilities or the like?

[null1024]

Something like AutoHotKey should do the trick.
I don't use it personally, but I've heard tons of good stuff about it.
also, mashing is part of Cho Ren Sha's fun ^_^