You should start by downloading any CW 10 documents for the part that you are targeting and read those. Other things you should consider are:
1) CW 10 is Eclipse-based. It requires more system resources than the "Classic" IDE. Weigh in the fact that you might have to upgrade a number of your development systems to run CW 10.
2) Since the CW 10 IDE is Eclipse-based, the UI is quite different from that of the Classic IDE. The build settings and debugger configurations are located in different parts of the Eclipse IDE, whereas most of these settings were located under the Classic CodeWarrior IDE's Target panel. You may need to consider some training, unless your development team is very familiar with Eclipse.
3) If you have a lot of software in old Classic CodeWarrior projects, there will be some pain in migrating them to Eclipse. There is a CodeWarrior project importer in Eclipse to help on this, but certain features and settings can be lost and you'll have to retool the project slightly to work under Eclipse.
---Tom