I have footages from both but I realised the audio drifts. I have no club how to do it scientifically as the XDCAM footage is through out the interview but the 5D2 is only bits and pieces.

The 5D2 is processed via Neoscene so it is 29.97p but the XDCAM EX is 25p. Any suggestions?

You can do this automatically with Plura Eyes software from Singular Software (Singular Software (http://www.singularsoftware.com)). Very afforadable too. For takes shorter than say 20 minutes I expect not much drift.

Does plural eyes conform the footages? I tried the H4n + 5D2 with Plural eyes but not XDCAM EX plus 5D2 from Neoscene yet. Will have a go tonight.