I've been looking around online for information concerning where I can farm Titanite slabs., yet all of the information I have found is outdated as the newer versions tend to change quite a few things. Simple question really, where do I need to farm to have a decent chance at these slabs dropping?
I believe this page is still accurate.
There are several places to obtain once-per-playthrough slabs, but I believe the Darkwraith enemy in New Londo Ruins is the only one that can drop slabs and can be farmed (because it respawns).
I recently got a slab drop from a Darkwraith (and I wasn't even farming for them), but it may have been just before the 1.08 patch was released.