I wrote an article on Installing PHP 5.3 in order to look at the newest features that have been back-ported from PHP 6. The result of this is my What's new in PHP 5.3 article that was published by SitePoint yesterday.
I won't go in to the nitty-gritty here, but suffice it to say the the new features will solve a number of problems. Read the full article to find out more about namespaces, late static binding, a new MySQL native driver and the other features of PHP 5.3.