If you are currently synchronizing your Active Directory environment with Live@edu using a tool like ILM or FIM 2010, you have a new option with Office 365. "DirSync". Not the DirSync of BPOS days-gone-by, but a new tool based on a customized and wizardized version of FIM 2010.
Whether you are currently using an out-of-the-box configuration or you have integrated customization with ILM or FIM, the recommendation from Microsoft is the same. After your upgrade to Office 365 is complete, Uninstall OLSYNC/OLMA and set up the Directory Synchronization tool.
Note: There is only a 64-bit build available, so depending on your environment, you may need to use a different server.
To acquire the software, you don't have to purchase a license either. It is included with your Office 365 subscription. Simply download it from your Office 365 admin portal. It's available on the user administration page next to "Active Directory synchronization."
Before you make any of these changes, be sure you confirm whether you are using any customization and you fully understand the impact of moving to this new tool. For environments with custom management agent code, Microsoft recommends contacting a partner to help assess the impact of the upgrade.
A few points to keep in mind:
PCNS for password synchronization is not supported in Office 365. If you are synchronizing passwords to Live@edu and would like users to have the same password in Office 365 that they have on-premises, you will need to implement Single Sign-On (SSO)
Federation for Single Sign-on should be implemented before directory synchronization is set up
The current limit for synchronized Active Directory objects is 50,000. If you have more than 50,000 objects in your Active Directory environment, you will need to contact support after your upgrade to have that limit increased
More information on the directory synchronization options after upgrade is available at the Office 365 Wiki page here: http://community.office365.com/en-us/wikis/live-at-edu-transition/directory-synchronization-options.aspx