You can probably find the information buried deep in most trusts,' websites, usually under the "for staff" section. It may not give much information online such as prices etc, unless you make direct enquiries.
You could rent there for the whole of Foundation programme if your trust had available accommodation and you wanted to, but I'd say it's pretty rare for doctors to do so these days. Some may move there initially as it's an easy option while looking for a private rental/houseshare, but I don't think many stay for the whole year tbh - but my experience is fairly limited as my F1 hospital had no doctors accommodation and I don't think anyone lived on site at my F2 hospital either. I've only used it once for a couple of weeks while waiting to move into a new flat, and occasionally for short stays if I'm doing consecutive nights/long days (I have a long commute).