According to this article from Insight Magazine, "Vice President Dick Cheney is expected to retire within a year."
The article cites senior officials who say that the VP "would be persuaded to step down as he becomes an increasing political liability to President Bush."
There are a lot of issues cited in the article, and I encourage you to read the article to get an idea of what is going around the scuttlebutt on the upper echelons.
I think it bears noting that the article is very definitive in its statement - he's expected to retire. This isn't a "sources say something might happen sometime in the future maybe," article. The fact that they cite "senior officials" also indicates that there might be more here than mere speculation.
Of course, much like Oscar predictions, only time will tell whether the insiders are right.