Standalone ISP Mod

[tomasreabe]

So this thing will work on blank chips http://ladyada.net/library/tools/standaloneisp.html
But what if you have a blank chip on a board. Could you use something like this to flash chips that are in system?
The one area that I see as a problem is that the chip on the board has its own crystal whereas the programmer connects Chip pin 9 to digital pin 9 so there is no crystal.
Is this needed to keep the chips in sync?
I can and have done the uploads thru the ISP with the computer but I am looking to save the time and remove the laptop from the program process. But I am using SMT chips so I want to solder up the board and then program.

Thanks for any help

[adafruit]

it could absolutely work with an onboard chip, just dont use the fake crystal oscillator.