I asked her to sign a sublet agreement and she got "deeply offended". She now says that she will spend the two months at her parents to save cash.

I was given less then one months notice of these new plans and I found my new roommate based on her old plans.

The lease says that one must give 60 day notice before leaving in order to get the deposit back. The landlords will not let me sublet to anyone other than her.

So if I don't pay her half for June 1st, can I insist that the landlords take it from her deposit?

The only thing I have is emails indicating her plans to stay the summer and the fact that I found a roommate for Aug not June.

She sucks, but what can I do to cover my losses?!! I see July's rent as lost, but can I use the 60 day clause to cover June?

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.

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.

Small Claims would be the place to find out.