To make it easier for Lotus Notes users to switch to Google Apps; Google released a new tool “Google Apps Migration for Lotus Notes,” that migrates mail, calendar and contacts quickly and easily. Key features include:

-Easy deployment Centrally administered server side migration process, requires no user intervention.
-Users can continue to use Notes with any downtime, even during the migration process. After they're migrated, Gmail will open Notes links in Lotus Notes.
-Migrate multiple Global offices simultaneously or separately. Assign administration controls at the organization and the office level as needed.
-Trackable reports Centralized event logging to manage & monitor migration across any number of Domino servers and sites

Migration from Lotus Notes to Google Apps:

If you're considering switching your users from Lotus Notes to Google Apps, talk to sales team or sign up trial now. 

Download: Google Apps Migration for Lotus Notes

Source:→ Google Enterprise Blog