How to make my program case - in sensitive?

Hi,

Iam writing a SELECT query in report for retrieving the address number by giving address details like street, city and post code.But my program is case sensitive such that if the user inputs either in Upper Case or Lower Case, it will not work.

For eg: suppose the city is Cape Town. If the user inputs like CAPE TOWN or cape town ( via Selection Screen ), then it won't work.

How can i make my program case- in sensitive?? please suggest..