If this is a Trane unit you should be able to remove 8-12 screws around the top lip of the unit and the fan assembly and lid will lift right off unless it has one of the newer plastic weatherguard tops then it is a little more complicated but still easily doable then with some gloves on or a bag over your hand you can clean out whatever is there put the lid back on and you are ok all you have to be careful of is the fan wires make sure they go back in the area where they are originally run if you have ayone to help you this becomes easier as your helper can just hold the top up 90 degrees from where it was originally positioned while you bend over into the unit to get the offensive material out and then just lay it back down when you are done.
By the way I have heard of quite a few animals perishing in AC units usually when it is cold and they are trying to warm up but this is the first suicidal snake I have ever heard of

Here is a link that might be useful: Air Conditioning Repair made Easy

Remove screws at the top of condenser unit and lift up the fan. Hose inside out.

Thanks, Miken and Shifrvb. It is a Trane...can I only go in from the top (I'll also go dig out the booklet about the unit)? The carcass is at the bottom--I have no idea how I'd reach it (hmmm, looks like maybe a pair of kitchen tongs is about to give its life, as well.) There are also leaves and such in there that I could clean out while I'm excavating.

I'd obviously have the whole system off, but should I also turn off the power, as well? (What a great way to have my husband spend Father's Day--helping me clean up after a kamikaze snake!!)

Cuffs, thanks to you, too...I think we were writing at the same time and I didn't see your post until after I finished my last one. I think I'll defninitely turn off the circuit for the unit when I attempt this!! All this agita over a snake who wanted to ride the merry-go-round.

Cuffs, thanks for a great, big belly laugh!

The snake liked all the heat being dumped by the condenser.
Open up the top and remove as much as you can with the power OFF.
You do NOT want the unit to start up (including the fan) while you are in there or you will have the same problem as the snake.
Use a garden hose from the outside of the unit to push 'stuff' off the coil, then clean it out.
A shop vac works very well for this.
Be sure to empty the vac before it starts to grow other things in the tank on the debris.