Michael, the single longest chapter in my book is about air conditioning retrofit and rejuvenation.
Basically, any time you open up an a/c system, you need to replace the receiver-drier so the system has fresh desiccant to remove moisture.
Then, as Bill says, it's a question of exactly what went wrong with the compressor. If the compressor just blew a seal (no, that's just ice cream... sorry :^) or if the clutch let go, new compressor, new drier, evacuate and recharge, Bob's your uncle. But if the compressor seized, it may have thrown a whole variety of contaminants (metal shavings, pieces of teflon o-rings, etc) into the system, requiring that the system be flushed out. And by the "system," I mean everything -- the condenser, the hoses, and -- egads! -- the evaporator. As you probably know, it is a colossal freaking pain in the butt to pull the console and evap assembly out and expose the evaporator core, but if there is widespread contamination, that's what needs to be done. The expansion valve should be changed as well.
What I typically do in resurrecting a dead system is undo the compressor and drier hoses, look at them, and swab them with a Q-tip. You can also pull out the drier and tap the ports out onto a paper towel. It's also smart to pull the hoses from the condenser off the compressor and the drier, blow through these hoses (that is, blow through the condenser) with compressed air, and tape a white rag on the outlet and look at it. If a black ooze is present anywhere, you have major problems and would be well-advised to replace virtually every single hose and component, as you'll never flush it all out. If the contamination is a light powdery residue, or some isolated metal flakes, you can probably get away with flushing it with AC flush or mineral spirits followed by brake cleaner (what I use). If it looks clean, you're probably fine and probably don't need to flush.
Note that if you're changing refrigerants (R12 to R134a), you DO need to flush, as you need to get every trace of the old refrigerant oil out.
As Stevehose said, if the system is open anyway, now's a great time to upgrade to a parallel flow condenser. I bought one that I sized as the biggest one that'd possibly fit (I'll check what size it is when I get home), but my system keeps cooling, so I haven't taken it apart to upgrade it yet.
Good luck!
--Rob
