ubun2

When i installed ubuntu on my windows vista machine, i had two menuitems for ubuntu and two menuitems for windows vista in the grub boot menu. I edited the boot menu list file and set vista as my default boot operating system. So, if i don't hit enter, it by defaults boots into windows.
Since i use both operating systems, after running ubuntu update manager, the boot menu items is growing. Looks like it is growing whenever there is a kernel update. How to fix this so that i only have 2 menuitems of the latest ubuntu version and recovery mode and also the windows menu items.
Here is how my boot menu looks like
==========================
ubuntu 9.04, kernel 2.6.28-15-generic
ubuntu 9.04, kernel 2.6.28-15-generic (recovery mode)
ubuntu 9.04, kernel 2.6.28-14-generic
ubuntu 9.04, kernel 2.6.28-14-generic (recovery mode)
ubuntu 9.04, kernel 2.6.28-11-generic
ubuntu 9.04, kernel 2.6.28-11-generic (recovery mode)
ubuntu 9.04, memtest86+
Others operating systems:
Windows Vista (loader)
Windows Vista (loader)

 
Please help how to fix this?