Joel,

Talk a look at Philips application note AN-461. They have a schematic of a product they no longer sell that does what you want.

Philips has a new series out that no longer requires 12Vdc for ISP Flash. AN-461 is for their RX+ series and thus has a 5V to 12V converter.

I used the AN-461 circuit as the basis of my lab-bench programmer card.

-Jay C. Box