g1smd - 1:47 pm on Mar 21, 2011 (gmt 0)
In Apache those would be two different pages/folders. They would target two different files/folders in the filesystem.
In IIS those would cause you a Duplicate Content problem as both URLs would return identical content.
Make your life simple, go all lower case for everything.
If you use URL rewriting, make sure that only one canonical version of the URL can return content and the others either redirect to the canonical URL or return a 404 HTTP status.
Additionally, avoid underscores and spaces in URLs, those also cause problems.