PTO: It just came out in beta, and there hasn't been much discussion yet about use, statistics, etc. I'm assuming that it will be a useful tool once you get a database.
Cold-calling: I would limp preflop with A2xx, I would not cold call a raise. The raiser probably has A2xx also, so if there is a low, and if the other idiot doesn't jam with his nut low and drive out the dead draws, you get quartered and maybe break even.
Aggression: There are no made hands preflop in O8, and therefore every hand is a draw at this point. I rarely raise preflop. About the only exception would be a very strong hand (such as the magical AA23 DS) in the cutoff or button. One good place for aggression is on the flop, if you have all high cards and 2 high cards come on the flop. I bet/raise here to drive out the low draws, increasing the chance to scoop.
Variance: O8 generally has less variance than a similar game of HE. You should be winning more pots in O8 than in HE, though most of those will be split pots. The split pots should keep you even, and the occasional scoop will be the gravy.
Resources: The O8 book by Tenner and Krieger is a good intro to the game. Zee's book is the current bible. The SS2 chapter is pretty good; I'd rank it in between the previous two. Ciaffone's book is THE book on Omaha, but lacks depth on O8. Cappelletti's book on O8 is also very good. Two very good web sites are
Steve Badger and
Crockpot
I have the strategy guides from both sites printed out and in a 3-ring binder, and I reread them regularly.
Profitability: Take a look at Mike Cappelletti's articles at the CardPlayer web site. He has a lot of good stuff there. One of the things he talks about is that, unlike HE and regular Omaha, in O8 the good player has a very big edge over the bad player, but an expert player has only a small edge over a good player. He also talks about Cappelletti's Rule, which is that in a low limit 10 player game, you want an average of 5 or more seeing the flop. If it's 4 or less on average, it's best to find another game if possible.