To selectively remove items from your Address History it is a Registry edit. I believe there is a tool, or two, that can aid you in doing it, also.
Are you sure you want to do those sort of edits?
I can do it, and I have done it, but if it isn't too annoying, it will fall off by itself (be removed from your list) after a period of time, AS LONG as you never go back to that same site, during that period. I think that period of time is based on your Tools>Internet Options, General, History - Days setting.
Let us know if you want the steps to manually edit the Registry. Otherwise, I'd say live with it.
You know how as you type in web addresses it drops down and shows other sites you've been to?
For example, as you type in www.msn.com it'll show all these sites that start with 'm' that you've been too until it matches up with 'www.msn.com'
How do you get rid of those?