What is the maximum size limit in GB of a Microsoft Office Outlook 2003 PST file?
It's actually configurable by registry. The default size limit is 2GB for Outlook 2003. If you are using the Large File Format, the limit is 20 GB.
For more information about configuring it, read here.
In Outlook 2002 and its earlier versions, .pst file is in ANSI format and its size limit is 2 GB. In Outlook 2003 and 2007, .pst files are in Unicode format and by default the limit is configured as 20 GB.
For more information visit - http://support.microsoft.com/kb/830336