Could anyone tell me how to draw a circle in GIMP ???

What is GIMP?

GIMP is a painting/drawing software which works under Linux (there also is a Windows version but I don't like it so much).

Use the elliptical select tool, hold down CTRL key to constrain as circle, fill the selected area with new color, right click on selected area, choose SELECT, SHRINK, shrink selection by whatever number of pixels you want your circle width to be, right click again in selected area, choose EDIT, CUT. Voila, one beautifully antialased circle.

found the answer here.

http://www.rru.com/~meo/gimp/faq-user.html#circle
check this out.
http://www.gimp.org/