The new version of BentleyView is capable of reading Microstation and AutoCAD formats and is free. If you wanted to be able to mark up AutoCAD and Microstation drawings you could try Bentley Redline. It is free for Select Subscribers.
V8 does have a batch converter that will allow you to convert al of your V8 drawings to V7 or Autocad or into a different V8 standard if that is what you are looking for. You can set up how it converts levels, color, font, etc. There are articles on the Bentley website and askinga on how the...