Often times easier than recompiling the whole kernel, when only a single module needs to be rebuild inside the tree. Of course, you need to keep your source tree around and dirty.
faith:/usr/src/linux-2.6.9/net/sched# make -C /usr/src/linux-2.6.9 SUBDIR=`pwd` modules make: Entering directory `/usr/src/linux-2.6.9' CHK include/linux/version.h make: `arch/i386/kernel/asm-offsets.s' is up to date. CC [M] net/sched/sch_sfq.o Building modules, stage 2. MODPOST LD [M] net/sched/sch_sfq.ko make: Leaving directory `/usr/src/linux-2.6.9'