I'm interested in upgrading MacBook Pro OS X 10.6.8 to Yosemite so to access my ICloud account; I want to understand ramifications and if I need to upgrade my apps and if so, what happens to my IPhoto and IMovie data

Check that your computer is compatible with Mountain Lion/Mavericks/Yosemite.

To check the model number hold down the option/alt key, go to the Apple menu and select System Information.

• iMac (Mid 2007 or newer) model number 7,1 or higher
• MacBook (Late 2008 Aluminum, or Early 2009 or newer) model number 5,1 or higher
• MacBook Pro (Mid/Late 2007 or newer) model number 3,1 or higher
• MacBook Air (Late 2008 or newer) model number 2,1 or higher
• Mac mini (Early 2009 or newer) model number 3,1 or higher
• Mac Pro (Early 2008 or newer) model number 3,1 or higher
• Xserve (Early 2009) model number 3,1 or higher

Your Mac needs:

• OS X v10.6.8 or OS X Lion already installed
• 2 GB or more of memory (More is better - 4 GB minimum seems to be the consensus)
• 8 GB or more of available space

Check to make sure your applications are compatible. PowerPC applications are no longer supported after 10.6.

Application Compatibility

Applications Compatibility (2)

Do a backup before installing.

Your iMovie and iPhoto data should be good, but you will have to upgrade the applications.

If you decide the upgrade isn't worth it, you can share Mail, Calendars, and Contacts running Snow Leopard. Based on my experience, I don’t recommend syncing Contacts - created a lot of problems with duplicates. If you have 2 step verification enabled on your Apple ID, you will need to generate an application specific password for Mail, iCal, and Address Book. Apple ID - Manage

You are welcome.