If your small business uses Apple Macintosh computers AND it is also an Intuit QuickBooks shop, you might want to wait before upgrading to the new Apple OS X 10.8 release (aka Mountain Lion). That's because the release may or may not be compatible with QuickBooks versions earlier than QuickBooks 2012.
If you're a registered user, you should have received a notice alerting you to the fact that Intuit won't promise to support you if you upgrade to Mountain Lion and have an issue with QuickBooks 2011 or earlier editions.
According to the note that I received myself (I'm a QuickBooks 2011 user):
"If you decide to upgrade your OS, you may find that most things in your QuickBooks for Mac work for you, but if you run into a problem, we may not be able to help you. To minimize the chances of running into issues, you should make sure you've installed the latest update for your software."
Right, Intuit may or may not help you if things go wrong.
If you can't resist an operating system upgrade (I'm sure the Apple download servers will be challenged today as is usual with any Mac update) and you still want to run an earlier QuickBooks version, Intuit recommends setting up a partion to run it. Otherwise, you'll need to upgrade to QuickBooks 2012.
What other software might give you problems if you decide to go with Mountain Lion? You should read this post by ZDNet's Apple expert, Jason O'Grady, for other resources you should consult before upgrading.