Haha, nah - that was Windows XP 64-bit, they wanted to release but didn't.
Longhorn is planned later second quarter of 2006, so about May, June, possibly July. It will be about what XP is now, with extra versions with prices dotted around the Professional and Home Edition Tag.
Haha - you should shoot whoever told you that Because he's a crackpot.
Few Enterprise Server Systems have a Terabyte. It would not make sense plus it has to go on a DVD, at most on a HVD but it won't because not enough people will have that by Longhorn. So yeah - its 5 Gigs for the Install Disc and at maximum 7 Gigs on the Computer.
It will require I would imagine only 1 Gig of RAM, preferably. Processor speed requirements are always vague - for XP they depend entirely on how you would like to use it. On Longhorn, for best quality Processing, I'd imagine nothing less that 2.6, 2.8, better something over 3 but yeah - it depends how you want to run it. 2.4 probably wouldn't be too bad. It will of course run on 32-bit and 64-bit machines, probably different versions.