Same problem here, but this is a brand new imac with 10.6.3. Can't print any text or graphics in color, but no problem printing photos.
Ran software update, restarted no good.
Repaired disk permissions, restarted, no good.
Downloaded complete driver package from HP, restarted, no good.
Repaired disk permissions, restarted, no good.
I have tried in iwork, word, excel and mail and none can print in color. Iphoto, aperture and photoshop can print in color.
Printing from the previous computer running older software is still fine.
Searching the web it seems that there a fair number of people having similar problems, with HP, Epson and Lexmark printers so it isn't a manufacturer specific or driver specific issue. This seems to be a 10.6.3 issue....