Longhorn!!!!???????

Hey I`ve been hearing about the term "Longhorn" for quite sometime but yet I don`t know what is that "Longhorn".
So can anyone tell me that what is "Longhorn"..

it is basically windows xp 2nd edition...still in development and then next one after is Blackcomb...they get all these names from ski resorts...xp used to be called whistler before it went gold.

Hey thanks!!!!!!!!!!!

or is it different slopes not sure now.