You can use this Java applet to pick colors for text and its background.
Thanks to the author of this applet, firstname.lastname@example.org
Color Picker Instructions
Use the sliders to adjust the red, green, and blue values of
a color. A swatch will automatically adjust
in the upper-left corner COLOR box showing the color defined by these values.
You can also type numbers directly into the Hexadecimal or
Decimal boxes to set the color.
Hit the Enter key after you type a number.
When the COLOR box shows what you want for the text or background color, click on
the "Set Foreground" button to set the text color or the "Set Background" button
to set the background color.
The box below the COLOR box shows what
your current picks for the text and background look like together.
When you are satisfied with your combinations,
get the numerical color codes for these
colors by clicking the "Get Foreground" (to show the text color code)
button and "Get Background" button.
You might also try out the Color Stepper which allows you to mix your own color charts.