In ring games blind stealing is profitable and people often steal too often or too little. The one problem I have is when to defend against a blind steal, does anybody have any good advice or articles that talk about this more in depth?
Stealing/defending blinds in a ring game is a leak. Plug it.

The blind is such a small portion of a stack in a ring game that it's too much risk for too little reward. You can easily lose a good portion of your stack trying to protect or gain a tiny percentage. Risk/reward is out of sync. The only exception is if you are trying to set the blinds up for a move later in the session or are trying to build that LAG image. But if that's the case you're doing more than stealing blinds anyway.

Blind stealing done correctly in a SnG is the difference between cashing and bubbling out. The basics are steal when the table is tight. Don't pick on the big stack unless it's the bubble. He has the chips to defend and put your stack/life at risk. No need to court danger. UNLESS you've seen evidence of him not defending, then go for it but be careful.

If you get caught and have nothing, get out. Try again later. Careful of picking on a tiny stack, they're as likley to raise AI on you with any A/K or broadway card as they are to fold. Medium stacks are the most suceptible, they are trying to limp into the money. They tighten up and figure to outplay you when they are guarenteed something back.

Blind stealing is an art. You have to feel it. know the table, know the opps, know your image.

As far as defending...Can't help. I rarely defend my blinds unless I'm getting picked on repeatedly, then I call the bet and lead the flop. It's dicey though, I prefer just to steal other's blinds to compensate for the blinds I give up. I typically play pretty aggressively which also serves to limit the number of times I get picked on.

Oh and the two main things about blind stealing.. YOU DON'T HAVE TO GO AI TO STEAL THE BLINDS. Why risk your stack when the threat of your stack is enough? Live to fight again another hand. AND:
Don't steal the blinds when they are 10/20. Who gives a damn if you just added 30 chips to your 1500 chip stack? It makes no difference in the scheme of things and your stack is in jeopordy for very little return.

Damn, I'm gonna lose so much money now.