tools to update attributes in AD

I have a task to add data to the manager attribute in Ad (we've recently migrated to office 2010 and lync2010) and want to use more of the attributes in AD.  I've been given a spreadsheed with 600 employees and how each users manager is.  I've been trying to write the ldifde file to do the import,  but at the rate I'm going it would be easier to just manually make the edits.  Is there any tool out there that will allow me to import a spreadsheet of attributes, and either create the ldifde import file to midfy the existing users attributes,  or just do it from the tool??


Thank you.