Best way to execute a SQL script ?

I am a software engineer about to release the next version of my software
which runs on SQL 2k. Since the last release I have altered, added, and
dropped many tbls, sps, views, triggers, etc. I have a fairly huge t-sql
script that when run will update an exisiting db to the new structure. My
question is, what is the best way to execute this script. I won't have
access to the client installations physically or through MMC. I think I will
write a VB app that the user will run on the SQL server and it will in turn
execute the script. But how do I do it?
Do I shell out to isql ?
Can I use DMO ?

What is the best, safest way to have an install/patch program execute a huge
t-sql script ??

Thanks
Josh