If the module you want to include is mavenized, get BOTH the api and omod jars from the target folders and "mvn install" them.
In that case, the omod renaming goes like this:
mv $moduleid-$version.omod $moduleid-omod-$version.jar
If you are using Windows, use svn to check out the entire module on which you are dependent. You can find the omod/jar files in your Eclipse workspace. You can follow the same steps by using MS sytax
<environ var>=<value> BECOMES set <environ var>=<value>
$<environ var> BECOMES %<environ var>%
You can either copy the 2 files to a temporary location and rename the omod there, or you can copy the omod file to its new name; you want to make sure the original file remains in your Eclipse workspace.
Your life will be easier if you add %M2_HOME%/bin to your path (through My Computer>Advanced>Environment Variables); the maven doc erroneously says %M2_HOME%
Installing omod to openmrs maven repo