The Camel Extra project uses Maven as its build tool. If you don't fancy using Maven you can use your IDE directly or Download a distribution.
mvn install
The following avoids running all the unit test cases
mvn -Dtest=false install
If you prefer to use an IDE then you can auto-generate the IDE's project files using maven plugins. e.g.
mvn eclipse:eclipse
or if you have an older version of IDEA then try this (IDEA 7.0 can open pom.xml files directly)
mvn idea:idea
If you have not already done so, you will need to make Eclipse aware of the Maven repository so that it can build everything. In the preferences, go to Java->Build Path->Classpath and define a new Classpath Variable named M2_REPO that points to your local Maven repository
<user>
.m2\repository
See the Release Guide for more details