I have a beta version of 10.6.5 installed. Build 10H542. How do I upgrade it to the latest release that just came out today? When I run software update it tells me I'm up to date.
Why do you have a beta version installed if you haven't read at least the basics like that? The answers are all available on the ADC site.
AFAIK, btw (I'm not a dev), you can download and install the combo update from Apple's Downloads section of their website, and that will allow you to upgrade to the full release version. Software update doesn't work to upgrade you from beta releases, however.
WARNING: It seems the Combo Updater I linked to below to is a bit frelled, according to the "Apple Releases Mac OS X 10.6.5" thread, thus use with care.