What do you need it for? Don't you have mem.exe?
By the way, the program's name is in the MCB, you won't reliably find it in the PSP because the area where the program's name is stored is cannibalized by DOS when doing some file I/O. It's in the last 8 bytes of the MCB if my memory serves me right. This enhancement was introduced in DOS 3.3 I think.
Supposing you know the address of a certain memory block, its MCB is in the previous paragraph. To determine the next MCB, just add the size word in the MCB to the address of the current MCB, +1 paragraph.
I don't know how to locate the first MCB in the chain, however. Try disassembling mem.exe. "Information has a tendency to be free. Which means someone will always tell you something you don't want to know."