Many Office 365 professionals know about the Office 365 Deployment Readiness Tool - http://community.office365.com/en-us/forums/183/p/2285/8155.aspx. This tool does an assessment and gives you a report on numerous things such as domains, active directory, Exchange, SharePoint, Lync, network ports, etc. In many cases, this report will provide many tasks an organization will have to do for AD preparation and remediation.
Microsoft has just released a new tool called IdFix. The purpose of this tool is to help customers remediate AD objects / attributes for a pilot or migration to Office 365 significantly quicker than before.
Here is where to download the new IdFix tool - http://www.microsoft.com/en-us/download/details.aspx?id=36832