also

alternatively, gtalksms.

Once you get it configured to not be too annoying, which involves:

Creating two separate jabber accounts, one for your phone to notify you and the other for your pc to receive the notification (might not need to do the last step and could use your google account)

Getting the notifications right

it will:-

- tell you in the status the battery level

- IM you if the phone is ringing

- IM you if you receive a text

- you can reply by replying to the message

and you can do a bunch of other things like simulate ringing, take photos etc. etc.

Freebie (but to be fair not top quality yet)

http://code.google.com/p/gtalksms/

Half way there

If it's waterproof and works in the bath then I could be convinced to get one.