making lowercase user names

[sfast]

There are 50 users registered in an application. Logon is case sensitive.

eg-
PrepstClau2000PC2
PrepstClau2000PC3
PrepstClau2000PC4
PrepstClau2000PC5

I have to make their names lower case.
like -
prepstclau2000pc3. How can I achieve this in a sql query

Thankyou.

[coopster]

The string function

LOWER()