I'm researching the landings at Saipan by the 2d Division's 6th Marines and am trying to establish which units (company by company) were a part of each specific "wave".
Does anyone have information about this? Or know of a good source?

Go to the Combined Arms Research Library at
http<colon>//cgsc<dot>leavenworth<dot>army<dot>mil/carl/contentdm/home<dot>htm

- click the go button next to "Advanced Search"
- type "forager" in the "all of the words" blank
- select only WWII Operational Documents
- click search

Some of these documents are pretty big, so they're broken down into chunks, but even the chunks are still pretty big. If you don't have DSL or better, you will be in for some very long downloads.

Anyway, you might find what you're looking for here. If you don't, well, you'll find most everything else you'd want to know.

Yes, that is really a great site for all types of original historical military documents.
Unfortunately (for me) I've already downloaded and read about everything they have pertaining to Operation Forager (Saipan).
So, unless I missed it in my reading of the documents, what they have does not go down to the level of detail that I'm looking for. Their documents state which battalions landed on which beach, but not which Company was assigned to which landing wave on that beach.
Thanks for the suggestion, though.

You might try the Marine Corps Archives and Special Collections. The have a web site: http://www.tecom.usmc.mil/mcu/.../Archive/default.htm
On the Research Collections page they have a listing for "WWI & WWII Operational Orders and Reports".

The Marine Corps Archives is an exceptional resource. They have provided me with copies of many original documents. I should also add that their staff are the most courteous and accommodating people I have dealt with to date.

Unfortunately, the on-line access to digital copies of the records went off-line early this year during a website re-vamping and has yet to reappear.

The problem now is that you must know the name of the specific document that you require in order for them to provide it. They just don't have the staff resources to perform the type of generalized searches that you could do on your own when the documents were still on-line.