Sounds like you're probably stuck, because you had a written lease that included her through 6/1, but just a verbal agreement (because she refused to sign a two month sublet) for July and August. I don't see how you can 'demand' the landlord take her half of June rent out of her deposit if her end of the deal expired June 1.

How is her end of the deal over if she hasn't given notice?

I suspect you could probably take her to small claims court or at least threaten it to get her to pay her share. Someone here could probably recommend how to go about that.

nf23, I just received your email today (after I posted the above comment). Thank you for the nice compliment, btw. ;)

I reread your post again.

Just wanted to clarify:
She had a lease that expired 6/1/2007. A written, month to month lease that did not extend beyond 6/1/07. In other words, did the month to month lease involving her 'officially' terminate on 6/1/07? -OR- was the lease month to month and 6/1/07 was just the beginning of a new month, and not the final expiration date?

I truly don't know if the emails would hold up in court as sign of commitment on her part. I would tend to think not (people talk about things all the time, following through is often an entirely different matter.) However, all kinds of things are acceptable in court it seems, so perhaps a judge would rule that her emails were sufficient enough to bind her to the agreement (an unofficial 'promissory note' for lack of a better term).

If you can fill in a few blanks, and clarify a few details, perhaps we can offer more accurate advice to help you out of the unexpected bind you're in.

you might be able to make her pay YOU--her e-mails would be proof of a verbal contract, and a verbal contract is binding.

Small Claims would be the place to find out.