How to change the instance name of SQL Server Express 2008?

There is no way to change the instance name without re-installing, sorry.....

Update: OK, seems there are a few ways of doing this - not sure how well these work, though. I have not ever heard of anyone doing this successfully, though :-( The easiest way to do this is re-installing with the correct name. Especially with the SQL Server Express versions, it's really no big deal to reinstall - done in a breeze, and you can of course backup and restore your data - so no loss there, either....

Also, it seems that method is limited to SQL Server 2000 only - when searching for the appropriate topics for SQL Server 2008 (sp_dropserver, sp_addserver), it seems those are used for renaming a server (computer) to a new name - not changing the SQL Server instance name, in my opinion. There's no more mention of renaming an installed SQL Server instance with that method.

sp_dropserver and sp_addserver are only used to tell the SQL Instance that the name of the physical computer has been changed.

There is no way to change the name of the instance without reinstalling SQL.