The Xen kernels are commonly asked for code already in place.
To obtain the already built modules:
wget http://www.quantact.com/dl/2.6.16-xen.tgz
To compile your own modules:
wget http://www.quantact.com/dl/xen-source.tbz2
tar -xjf xen-source.tbz2
cd linux-2.6.16-xen
gzip -dc /proc/config.gz > .config
make menuconfig
make modules
make modules_install
If you get errors on the make menuconfig stage, be sure to install ncurses-devel.
When selecting modules to compile under make menuconfig, toggle the “M”, not the “Y”.