I took the Tiger plunge this weekend. Overall, it went smooth. But I don't care much for Dashboard, and I'm having problems with Spotlight (a common issue it seems).
I did an upgrade install (I'm brave, I guess). All my UNIX builds made it thru. The only hitch was Apache - my httpd.conf was saved to httpd.conf.user_modified and none of my changes were added back to the new httpd.conf. Which means that Apache was using Apple's PHP. A quick update to httpd.conf restored my PHP and MapServer.
If you did an Upgrade install and are not up to editing httd.conf, here's what you can do: delete
/Library/Receipts/php4apache.pkg; reinstall my PHP package. Simple.
If you do an Archive and Install, or Clean/Erase install, it looks like there should be no problems installing my packages on Tiger. But I'm not sure about Tiger Server.
I have a report that the build instructions also work as is on Tiger.
I hope to start working on Tiger builds (and a few updates) soon. I expect backwards compatibility to Mac OS 10.3.6.