Microsoft has released a deployment kit that describes what they define as the "standard deployment method" for upgrading Exchange 5.5 to Exchange 2003 (including domain upgrade). The target is medium-sized organizations which they define as approx. 200 to 2000 mailboxes.
The kit contains three documents (and a small checklist); the first of these takes the reader through the high level deployment steps and a decision flowchart to check whether or not the readers organization is a candidate for the "standard deployment method" - the second document contains instructions for an in-place domain upgrade and the last document contains instructions for upgrading the Exchange environment.
IMHO one of the best features of this deployment kit is that it has an reasonable size (less than 80 pages) and that it gives the reader a very good overview of the steps in a standard Exchange/domain upgrade - whether or not the "standard deployment method" is a viable method for all readers is another case; but more important is that it gives the reader a good background for e.g. a discussion with their professional advisors regarding deployment methods.