/nay
Old indeed, official website :
http://www.gwx2.co.nr/
You can never login more than once on the same account.
But this tool allows you to run 2 different accounts on the same computer.
There are more projects like this that allow more then 2 clients aswel.
Like this one for example :
http://www.guildwarsmagic.com/
Those do NOT patch the gw.exe itself, some others do.
Patching = modifying guildwars executable is considered hacking.