From OCAU Wiki
Itanium is the name Intel has given to it's enterprise class 64-bit processor lineup. Similar in ways to other 'big iron' CPUs like UltraSPARC, MIPS, the RSxxxx series, and IBMs Power CPUs, Itanium is a 64-bit VLIW processor from the ground up, a completely different design to any of Intels or other CPU manufacturers other products.
Itanium was designed by both Intel and HP engineers, and as such there are some evident PA-RISC style features found in the core. Intel calls Itaniums architecture EPIC (Explicitly Parallel Instruction Computing).
Making use of the IA-64 (Intel Architecture 64-bit) instruction set (not to be confused with x86-64), the execution core is highly pipelined and parallel, but this means for optimum code performance, special compilers must be used to pre-order instructions in a way to make best use of the CPU, as the instruction scheduler has been cut back.
In benchmark results, Itanium makes a very strong lead against many of the other enterprise CPUs, especially in floating point math, and database like activities.
Being aimed squarly are the big enterprise, you'll most likely not see many (if any) Itanium based computers, but for interests sake, heres some manufacturers offering Itanium systems: