I have been using this hack for AGES now and have not gotten banned or even a warning. With the addition of achievements, I was able to explore all of the eastern kingdoms, azeroth and outlands in about 2 hours. it would have easily taken 5 or 6 to travel everywhere. I have also used this hack to capture the flag in WSG in under 75 seconds. This hack is amazing and I would recommend it for anyone.
http://mhs.mpcforum.com/MHS5.004.rar
If you are using vista, run as administrator.
To use: File> open process > wow.exe
then go to
tools > speed hack
choose what you like and BAM!! you are ready to go up to 22 times faster. its quite amazing.
If you have any questions, let me know!
UPDATE: VIDEO
[ame="http://www.youtube.com/watch?v=Ib3_1aAvyiw"]YouTube - MHS Speed Hack Demo[/ame]