Also keep in mind the Mountain Lion will be released Summer 2012. Mountain Lion ups the requirements a bit and drops some older Macs off of the list. Expected Mountain Lion requirements can be found here.
Do you have to upgrade from Leopard to Lion?
No. Leopard will continue to function as it always has on your Mac. By this summer, however, Leopard will be four versions back of OS X and it will be difficult to find new software that will run on it. But as I have always said - if you are happy where you are, you don't have to upgrade if you don't want to.
If you are a current MobileMe user, you meet the requirements for Lion and/or Mountain Lion and you do want to upgrade to Lion, here's how it works:
- Go to this link and log into MobileMe.
- Enter your address info.
- Install Snow Leopard from the DVD.
- Go to the Mac App Store by choosing Apple / App Store... from the Menu Bar.
- Purchase Lion for $29. There is no install DVD - Lion downloads from the Mac App Store.
- Run the Lion installer.
NOTE: MobileMe features iWeb hosting, iDisk and Web Gallery don't have equivalents in iCloud. As we get closer to the June 30, 2012 shutdown date, I'll give some recommendations on other apps that can take their place.