Sounds like a chicken and egg kind of situation: You need a preprogrammed 2051 for your 2051 programmer.

Perhaps what you need to do is to get an ISP-capable 8051 derivative, program that with the same code that would go into the 2051 on the programmer (the 2051 code should run as-is). Then build the programmer with the programmed 8051, program the 2051, and you're all set!

Funny how if you were interested in ISP a lot less work is required. Unless you just buy the preprogrammed part.

One thing that doesn't get mentioned much in the parallel/ISP programming debate is the newer and more capable 8051 derivatives tend to be available mostly in surface mount parts which are more difficult to parallel program...an inexpensive programmer gets a lot more expensive when you add adapters for the various non-DIP packages.

I find surface mount packages easy to work with (sometimes easier than DIP/through-hole), I like the smaller circuit boards and I love ISP.

Dennis