1. Download and unzip api:

wget http://xbee-api.googlecode.com/files/xbee-api-0.5.5.zip
unzip xbee-api-0.5.5.zip

2. Install

mvn install:install-file \
-DgroupId=com.rapplogic \
-DartifactId=xbee-api \
-Dversion=0.5.5 \
-Dfile=xbee-api-0.5.5.jar \
-Dpackaging=jar \
-DgeneratePom=true