I haven't tested it recently but yes it does work for premise customers as long as ISM is forward facing. If you do not have a URL redirect you will need to add /HEAT (must be caps) to the end of the url.
Also you only used to be able to use internal authentication with it.
Thanks Alasdair! We are forward facing and with your instructions I was able to authenticate.
Its challenging for us that its not available on the Android platform, and the overall UI/functionality is a second strike, so we'll probably hold-off on sharing this with our users and instead keep our fingers crossed for the responsive UI site.
The Self Service Mobile UI (what will be the responsive UI) may be a better option. I think the may be new apps coming down track next year for all platform types.