The tuning I showed you in my last entry was 'standard' tuning. Most of todays music is in standard tuning, or a variation of it. Other variations of standard tuning include:
Half-Step: Eb Ab Db Gb Bb eb (All strings are down-tuned half step.) Dropped-D: D A D G B e (The low E string is tuned down one step.)
Some of today's bands like to take these tunings and tune them down multiple steps. For example, System of a Down likes to play in Dropped-D tuning, down one and a half steps. Often referred to as Dropped-C tuning. Or on Metallica's latest album, St. Anger, they play in Dropped-D tuning, down 2 steps. Or Dropped-B.
You can mess around with your tuning, but try not to go much higher than standard, you would break strings a whole lot easier.