Not really sure what you're asking. The P4 is an 80x86 (or x86 for short), just like a P2, P3, AMD Athlon, Duron, etc.
SPARC is a RISC processor mainly (but not exculsively) used by Sun. The (now dead) Alpha architecture rocked. Then there is the Intel Itanium (sp) that is an island unto itself. The AMD64, which is really an x86 with 64bit register space, and so forth. The "Power PC" or PPC (found pretty much exculsively in Apple machines in the consumer space). ARM, StrongARM, MIPS, Moto Dragonball, and a whole host of others.
Not really sure where to tell you to go for more info. Google I guess.