In the table below, I've linked directly to the latest Microsoft Office service packs for each version of Office.
As of May 2013, the latest service packs for Microsoft Office suites are Office 2010 SP1, Office 2007 SP3, Office 2003 SP3, Office XP SP3, and Office 2000 SP3. There is currently no Office 2013/365 service pack.
Please keep in mind, however, that for most users the easiest way to install the latest Microsoft Office service pack is to run Windows Update.
Download Locations for Microsoft Office Service Packs
|Office Version||Service Pack||Size (MB)||Download|
 Microsoft Office 2013/365 does not yet have a service pack available. If Microsoft releses Service Pack 1 for this version of Office in a similar time frame as they released SP1 for Office 2010, expect Office 2013/365 SP1 in the first quarter of 2014.
 Microsoft Office 2013/365 and 2010 are the only versions of Office available in a 64-bit version.
 You must first install Office 2000 SR1a before installing Office 2000 SP3.