Apparently Illustrator and Photoshop uses different colour settings - Illustrator uses RGB and Photoshop uses some hex/HTML-like colour system with a combination of letters and numbers. Is there any way of 'translating' a RGB colour swatch to Photoshop easily?
Both Illustrator and Photoshop use hexadecimal values! The screenshot below: Illustrator is on the left, photoshop is on the right
You can use either RGB or hexa between the two programs.
To transfer simply select your swatch and open the Color Picker and select the hexadecimal value.
Fun fact: The first two letters/numbers of hexadecimal value colors are the Red color. The second pair are the Green colors, and the third pair are the Blue colors.
I hope I understood your question correctly.
If you want to match up PANTONE swatches... http://kb2.adobe.com/cps/330/330728.html