Haha! No, Itaniums are not like x86-64. They are x64 only. They won't run on superPi as they are not 64-bit...but don't worry. All their servers are 64-bit devices, so the drivers will work.
Usually, like Ownage said, Itanums are hyper-threaded, but the Itanium 2 is Dual core. They have these special socket, and I think they're called Socket P if my brain doesn't forget, and they have all the power of servers and all. Itaniums ARE expensive.
No, 32MB of Level 3 cache is on the Itanium CPU. It can be as low as 512k, and go as high as 32MB...or was it 24?
Since you seems wondered what it looks like,
CPU:
Socket and board
Then, you plug it in to an actual motherboard with an expansion slot.