If you have been tasked to work on a Lotus Domino to Exchange migration project, you will want to take a look at the following document, which goes into EXTRAORDINARY detail about everything you will need to know to make the transition.  Screenshots, Single-Phase Migrations, Multiple-Phase Migrations, Test Labs, Free-Busy connectors, you name it...  It is a GREAT read.

Microsoft Transporter Suite for Lotus Domino: This end-to-end guide takes you through the process of assessing your environment, planning your directory and mail transition, and executing your coexistence and migration plan.