HOSTS Secure (dowloaded
here) will update your HOSTS file on Windows startup, or you could schedule the update.
The options commands allow you to run the program on startup, and auto update the HOSTS file.
From my perspective that isn't ideal as I have a number of customised entries in my HOSTS file and the update process overwrites the whole file. I run Firetrust's Benign software to filter email content but since SP2 for WinXP was released I have needed to have a number of personal settings in the HOSTS file to get Benign to work properly. I suppose I could get around this by writing a little script to append my personalised settings to the HOSTS file after update.
If you haven't got personalised HOSTS file then the autoupdate is ideal.