Porting GUI to Kernel

Piyush
Hi Everybody 

I am developing a project in which I want to port uCLinux on an embedded
board and provide it a GUI.

Actually my board is consist of an ARM processor and other peripherals like
USB , serial port, and other many things.

and I have ported the embedded uClinux on the board and want to provide GUI
 
look to it . I want to display various gui widgets like buttons ,
scrollbars etc and also want to provide it with the small windows on which
I want to show what is happening .

So , can you tell me which GUI ( not commercial i.e open source) will be
good and how can I make it to talk to the uClinux kernel, I mean how can I
interface it to the kernel.

Thank you