Roughly, you have 4 options, listed in the order of ease of use:

1. buy a devkit with a derivative with on-chip debugging support. That's the most comfortable to use. The most popular is apparently the $99 SiLabs kit, but there are other lesser known options - ST's uPSD34xx, Ramtron Versa, Infineon's XC8xx to name just a few. The drawback is that you will stick to a certain derivative (and these tend to be pretty complicated compared to the "plain vanilla"), and these chips also come exclusively in the modern high-pin-density packages, making "home" usage cumbersome.

2. go for the UART-ISPable chips, such as the Atmel/NXP/SST/Winbond 'RD2 and family, DS89C4x0. These come in DIP40/PLCC44 of the "classical" pinout, so you can purchase a cheap devkit intended for any other derivative with the "classical" pinout, or you can build one on your own - there is no reason to provide a particular schematics as it is trivial and repeats infinitely - a simple wireup of the '51, MAX232, a power source and a reset circuit. One of the kits for which you will get support here is the 8052.com SBC (again, navigate through the column on the left).

As a bonus , you can get, that might perhaps appeal to somebody who sees the '51s as a reminescence to the Atari130XL... :-)

3. go for the AT89Sxx series, or P89LPC9xx. Programming both is not that easy and straighforward and has a lot of pitfalls, even if there are devkits for both available (as an example, the 8052.com SBC is originally intended for the AT89S8253).

4. in this group are antique chips and antique methods, not really recomended for a beginner

JW