Ways to increase poison DCs?

[Daftendirekt]

So, poisons are notorious for losing their usefulness at mid-late levels due to their static DCs. However, I know there are ways to increase those DCs. What are all of them? The only one I am certain of is the assassination (http://www.wizards.com/default.asp?x=dnd/we/20070314a) enhancement.

[thethird]

A recommended reading is the poison handbook, here (http://brilliantgameologists.com/boards/index.php?topic=4854.0).

Feats such as poison expert (Complete Scoundrel) would help, also if you have sneak attack there are various feats in drows of the underdark that work well with poisons, finally if you have a creature provide the poison and you can select its feats ability focus (the poison in question), virulent poison and deadly poison (from savage species) are good picks.

Also remember that anything that lowers a save effectively increases the DC of the poison