Ian Blyth has a great blog post up about integrating new software or change into a business - in this instance, Systems Center Operations Manager 2007. The five stages are essentially:

1. The existing status quo;
2. Resistance to change;
3. Chaos as change occurs, knowledge is updated and people learn;
4. Integrating the idea or software into the business processes; and,
5. The new status quo, at a higher level of performance.

Recommended reading.