Today is the day that Snow Leopard ships to the masses. But before you upgrade, you should likely take some precautions to make sure that everything goes smoothly.
First of all, MAKE A BACKUP. I cannot stress this enough as a lot of my work comes from people who didn’t do this before doing something major to their computer (and upgrading your operating system is major). I have a great resource for backing up your Mac here. By having a backup you can ensure that you can get your system back up and running with minimal pain should things go south. Oh yeah, the more paranoid among us would say that you should test that backup to make sure it works as a backup is useless if you can’t restore it perfectly.
Next, you should visit this page to make sure that the applications on your Mac are Snow Leopard compatible. Keep in mind that this list is one that is being updated constantly so the application that you’re looking for may not be on there yet. Therefore it pays to check back at a later date to see if it’s been added. If the apps that you rely on daily are not compatible with Snow Leopard, you may want to skip upgrading until updates come out. I should note that Apple themselves have as similar list, but it’s nowhere as detailed. But this list does describe the fact that if you do go ahead and update and the Snow Leopard installer comes across software that won’t work, it will punt that software to a special folder.
The last thing I would do is boot of the Leopard CD and run Disk Utility to verify the volume that Snow Leopard is going on. It likely wouldn’t hurt to do a permission repair as well.
At this point you should be good to go. One thing that I’ll do is I’ll note this Apple Insider document that details the changes in the Snow Leopard installer as it is very different than any previous version of OS X. This document will be handy for those of you who have done OS X upgrades before as you will know what to expect.
If anyone else has any other tips, please post them in the comments section and share your wisdom.