I didn't have hands on IPB yet, but reading this thread it seems that Injection Magic is easier to use. For those thinking to buy it here are tutorial links for creation of definition files and handling of custom morphs. I also added my own V4, ApolloMaximus 2007 and Sydney G2 definiton files:

http://posable.avatiser.com/en/1006/

Apollo 2007 Freebies Listing, free V4 and Apollo stuff