As you might guess, measuring antimatter is rather tricky: it's destroyed the moment it comes into contact with regular matter, so conventional approaches just aren't going to cut it. Give credit to CERN, then, as its Alpha group just measured antimatter for the first time. The team stuffed positrons (positively charged electrons) and antiprotons (protons with a negative charge) into a vacuum tube to create antihydrogen, with a "magnetic trap" keeping a small number of the anti-atoms in existence for long enough to measure them. The team then blasted the antimatter with a laser to study its positrons as they shifted energy levels, producing a spectral line.
The results aren't shocking -- surprise, antihydrogen behaves much like regular hydrogen (just with reversed charges). If it didn't, scientists would have to rethink their understanding of physics. The very act of measuring is important, though. In addition to shedding light on the nature of antimatter, it also tells scientists something about the nature of the universe. In theory, matter and antimatter should have destroyed each other almost immediately. The new findings don't explain why that didn't happen, but they suggest that it isn't due to the inherent nature of those substances.