The HD guide is supposed to make better use of wide screen tvs (16:9). Our current guide is just a stretched out version of the 4:3 guide. The new HD guide would give us an extra hour of programming. Instead of the current hour an a half of shows shown in the IPG there would be another hour tacked on. There would some other enhancements as well.
A good example of an HD Guide can be found on Shaw's own Cable TV website...