There are lots of books on process. My two favorites are:
Cockburn (1998), because he does a good job on focusing on the key issues in a short book. As such, I recommend this as a first book managing an OO project.
McConnell (1996), as he provides an in-depth look at best practices.
To find out more about the Rational Unified Process:
Kruchten (1999) is a concise overview.
Jacobson, Booch, and Rumbaugh (1999) is the source for more details.
If you are interested in a lightweight yet disciplined approach, take a look at Kent Beck's "extreme programming." It is a very different approach that emphasizes strong testing and evolutionary design. See <http://www.armaties.com/extreme.htm> and Kent's forthcoming book (Beck 2000).