First thing I want to say is that I decided to become an official beta after looking for one myself.
I wasn't looking for anyone to simply correct grammar/spelling mistakes, but to also give me criticism - harsh if needed. What I look for in a beta is also what I am as a beta. I will correct grammar/spelling mistakes, but I'd rather correct something larger than that, or at least point to a problem - like a paragraph that just doesn't fit, a chapter that doesn't really coincide with another, descriptions, OOCs, etc. I get very annoyed when the first sentence of a beta profile has a spelling mistake: and the mistake is "grammer". I cannot stand it, and I think I closed more than a few windows while looking for my own beta because of that.
Other things I won't stand are punctuation errors - it kills me, and if you're really terrible at it, I won't even want to correct your work - and someone who just cannot write. I hate reading fiction written by someone with no writing experience. It's just annoying to no end when everything is wrong - and I'm not talking about grammar and spelling.
I'm a great person to talk to, and I understand if a chapter is late. I write, myself, and read a lot.
I'm okay with yaoi and yuri, and can help writing both, although I don't know if I'd be that much of an aid while writing yaoi since I've never written any myself.
I can be contacted by PM, and I have a hotmail account, that I also use for chatting, so if you want live feedback, we can manage something.