Several security updates have been released for Outlook 2002/XP, 2003 and 2007. More details about these security updates can be found in their respective security bulletins;
KB973965: MS09-060: Vulnerabilities in Microsoft Active Template Library (ATL) ActiveX Controls for Microsoft Office could allow remote code execution.
KB957488: MS09-062: Vulnerabilities in GDI+ could allow remote code execution.
In addition, there are updates for the Junk E-mail Filter of Outlook 2003 and Outlook 2007.
The easiest way to get these updates and to install them is via Microsoft Update.
Note that if you are a home user and need support with these security updates, you’re entitled to no-charge support via your local Microsoft subsidiary.