secure login mysql

well I have a few login pages I have made that get info from SQL queries and the newest program I am writing has me interested in security and I am familiar with SQL injection. I havnt gone into writing anything or messing or even searching on how to protect from this my guess right now is search a string for SQL commands and remove them before I make the query but if anyone else has any experience with this and any advice I was just wondering what you think and how you protect your stuff.

Thanks