What should i be farming right now?

[nwo]

Most if all glyphs can still be created by northrend herbs. Stack as much as you can. Sell'em, after cata release, and before most people reach 85.
After cata release, few will farm northrend herbs. Cata herbs = high demand = exorbital prices, scribes will need "cheaper" herbs, sell them then.

I would suggest, if you have enough gold, to stack on saronite as well. Buy them now of AH for under 10g/stack. Sell them after cata for a tidy profit.

Stack up on cheap gems. People will need gems for leveling gear, and won't be so inclined to put cata gems (as their prices will be high).

And food/flasks/elixirs for the leveling purposes. Most wouldn't want to look for flasks during their leveling. They probably will stack them before the release.

I agree, cata herb prices can only go up since they pretty much hit rock bottom.

Saronite will also go up, but probably not too much, I also don't expect anyone to sell them for less than 10g per stack. I thought that they vendor for 10g? Or is that if you turn them into bars?

Cheap gems for sure, but make sure you buy uncuts, not cut ones... Blue gems on my server go from 3G each up to about 12g each for scarlet rubies. The xmute CD on epic gems should finally be removed once cata goes live (was supposed to happen in 4.0 but it didn't). Also, from what I have heard, the new gems will have iLVL requirements and as everybody knows, they will be extremely expensive and in extremely high demand for the first couple of months.

[Cuddleduck]

If i want to make a ton of gold when cata releases is there anything i can be farming atm? such things as ore or herb will these prices skyrocket?

All kinds of cloth then create bags to sell when cata hits.
Low level herbs from lv 1-375.
Low level ores from lv 1-375.
Rare stuff that's being taken out of the game.

This is all I could think of at the moment, remember that most who will be leveling a worgen / goblin at cata start, won't stop to level professions but rather powerlevel them once they reach level 85

[Therastos]

There are a lot of players doing Insane in Membrane at this moment, probably more than there ever will be. If you have a rogue, or are willing to level one, farming heavy lockboxes might be your best bet. You might be able to reach about 2000g/hour, or even more, depending on contracts you manage to make.

Other than that, I can't think of any predictable and significant price changes. You probably want to get rid of all your Wrath-stuff not used when levelling professions, such as high-end crafting materials like abyss crystals, BoE-items, gems, enchants, consumables, fish and meat and Sons of Hodir reputation items, but that's about it. Items that will be used when levelling professions will probably end up increasing in price over time, but I very much doubt the increase will be much higher than gold inflation (Rembmer, there is still a risk that they might end up decreasing in price if inflation is considered, and wealth bound in items is away from other business opportunities).

You could also try farming items like Azure Whelp, Hyacinth Macaw, or Disgusting Oozeling. There might be players who aren't aware they are not going away (correct me if I'm wrong), and pay absurd sums because of it. They are among better farmable items even without such misconceptions anyway. I wouldn't recommend that, though. In fact, farming in general tends to be much worse than playing in AH.

[Agape]

Herbs and ore from TBC and WotLK is what I'm mainly stocking up on, only the kinds used for leveling professions or crafting things which won't become redundant as Cataclysm hits, of course. If you've got the gold to invest you could just buy up those mats when they're listed for <60% of market price on the AH and mail them to an alt, lazy farming!

Whatever you do make sure you don't focus solely on thing, so that all your efforts won't have been in vain if Blizzard makes a last minute chance to the drop/spawn rate of that item.