Resurrecting skeletons in the Catacombs?

Weapon with holy damage should permanently kill skeletons.

Like Jitawa said using a divine weapon is your best solution it will permanently kill all the skeletons until you touch a bonfire. To get a divine weapon reinforce a weapon to +5 then ascend it at the blacksmith to a divine weapon. you need at least one green stone i forgot what its called. if you dont have any of those green stones then you can get some from killing the leaches at the bottom of blight town

Any divine weapon will do.An easy Divine weapon to find is Astora's Straightblade, put them down with that and they won't get back up again. (Note: Giant skeletons do NOT have to be dispatched with divine weapons) Astora's Straightblade can be found on the cliffs between New Londo and Blighttown, accessible immediately upon new game if you have the Master key, or somewhat later if you have to travel through Blighttown.

If your character can't use a sufficient holy weapon at this point you may want to take thaoxing1's advice. you can race throught the catacombs and kill the pyromance, quite an easy boss fight, and the skeles will stay dead. except the ones near the pyromancers. you have to kill those to or they will resummon the skeles that die near them. but once the boss is killed and the lesser pyromancers the skeletons will remain dead after one kill.

Okay guys Tarvos here in general there are three ways to stop the skeletons in the catacombs from reviving. One, like said earlier knock them of the cliff. Two kill the mages the guys who throw fireballs they don't respawn. three use a divine weapon to deal the finishing blow.

One of the armorers will make divine weapons,cant remember which one. I used a +5 divine battleaxe make's quick work out of them. You can farm green titanite down by the first bonfire in the depths by killing the blobs that drop from the ceiling.

A divine weapon with striking power, like a mace or morning star has the benefit of not only being able to completely put them down (allowing you time to find the Necromancer) but also causing them to 'shatter', allowing you to easily move behind and perform back stabs. Most people recommend other weapons, but be aware a divine weapon scales off Faith, so if you aren't a faith build, I've found this is the most RELIABLE method, since it works on all of the skeletons.