Thanks a lot for the above info.... I'm just going through the update process now.
It was actually quite painless though I had to restart the upgrade a few times but now all seems ok.
The only issue am having at present is rebuilding Ports....
I took the FreeBSD approach of installing everything via the ports tree instead of using pkg_add. I am not sure if there is a tool such as "portmaster" or "portupgrade" to rebuild all the installed ports?
Also another confusing thing is, out of the ports should I be building Stable or Snapshot? As my version of OpenBSD is now latest snapshot; does the Port version refer to that or is it a snapshot for the actual port itself so infact I should build Stable?