Photo Prints are coming out UGLY

[peterish]

A few friends and I will be putting up a portrait booth tomorrow at the mall, but so far the colors of the prints are coming out way too yellow. The images look fine on the computer and the colors are consistent when viewed on different monitors. We've tried different settings in Photoshop CS2, such as converting to RGB versus CYMK; Absolute versus Relative Calorimetric; letting Printer decide the color versus letting Photoshop decide...etc. Certain settings have been better than others, but they are all coming out with the color cast. Please please please help; this is a bit of an emergency. Thanks in advance!

The printer we've been using:

Canon i8500

[saxondale.]

Printing at 300DPI? Have you aligned the printing heads? Cleaned them?

I know my iP4000 can print horribly if these arent checked.