I agree with DanBot - skeletons seem like the perfect model for the "Army Painter method". Bone colored primer, a quick dip (or wash if you perfer), throw some sand on the base, and you're done. You would want to take more care with significant models, but this would be quick and easy for hordes of rank-and-file skeletons.
I was going to link the same thread, but Lord Tsunami beat me to it... I think I have also wrote my recipe on that thread, but here it is one more time: I spray paint with brown (It's Army Painter's range, not sure of the name, maybe Leather Brown or something), wash the crevices with Devlan Mud and then heavy drybrush (or an oxymoronic wet drybrush...) of Bleached Bone. If I feel like it, I might give it a quick wash with Gryphonne Sepia. For the talons, claws and bony protrusions of my Lizardmen I use Khemri Brown, Kommando Khaki and Bleached Bone, in that order and leaving a bit of the previous layer showing. I'm not sure how good that looks on bigger bone structures, like Stegadon's horns etc, though.