Put them at the begining of your script, and make sure you make them globale.
Just an FYI this is a bad programming technique. You should try to keep variables within the scope they are used. If you need info from one scope layer to another you should pass the info back and forth. Globals should only be used when necessary.
Simple minds, Simple thoughts!
I figure if you have the courage to get out of bed in the morning, then how bad can the day be.