If you're in the Army and want to make more money you need to get promoted, and since October 1, 2011 the Army now gives you more promotion points (10, in fact!) for earning civilian certifications related to their MOS. They also will provide money to help pay for any tuition, license, or exam fees needed to obtain the extra certification.
These certifications not only can help soldiers get promoted faster, but once you're out of the Army, these will show civilian employers additional skills gained while in the service - and the Army can help cover the cost! Check out the Army Credential Opportunities On-Line for more information on credentials for each MOS.