If you end your text with [/color] and begin your text with [color:#339999] it'll all come out with that tealy color.
Or just click on the "A" button (upper right, next to the smiley face) on the "Full Screen Reply" to get the whole color palette.
Highlight your text first, then click on the "A" and then the palette color you want. Same with bolding, quoting, etc.

...not TT