Visual Studio Hotfixes have been moved to MSDN Code Gallery. Previously they were only available by calling Microsoft Product Support or by searching through the Knowledge Base looking for relevant issues.
Even in its new home, hotfixes are being offered in a haphazard fashion. In order to find them one must search the Code Gallery for the term "hotfix". The sample query from Carlo shows 81 available hotfixes. These patches are not listed in any particular order and cannot be sorted. In addition, this site only contains hotfixes, full service packs for Visual Studio have to be located by another means.
As we mentioned in the past, Microsoft is still not supporting the "Check for Updates" command found in most versions of Visual Studio. Without this or any other mechanism, it is up to the individual developer to keep track of which patches have been installed.