I've been hearing a lot about turning Sims into NPCs, but that begs the question: What item/hack allows this? Can I have a link to this? I have a few characters I'd like to get rid of without fiddling around with the files...

There are various ones and you use them to create townies and townie type sims rather than NPCs per se. I use Inge's cat or the Sim Blender myself. It will depend on which type of townie you want to create - if you're doing vacation locals, you really need the townie brick. Sim Blender is probably the easiest to use. You can also do it with the in-game cheat townie gun though I don't think that gives you all the options (I forget exactly since I don't use it).

Cat: http://www.drealm.info/simlogical/s...Teleporters.htm
Sim Blender: http://www.simbology.com/smf/index.php?topic=20.0

I don't believe you can turn sims into NPC's, if by that you mean into mail carriers, bar tenders, nannies etc. You can make NPC's look like your playables with sim surgery which simply replaces their face. Townies are not the same as service NPC's.

Oh, yeah, I meant Townies.

I use the simlogical cat teleporter. Just click 'make townie' and they walk off the lot into townie land. Maxon already linked to it.

Alright, thanks! Now my model Sim which I never used can dissapear into nothingland...