It's listed in your manual (the exaclt mount type). And if you look in the Canon section you can see a lot of lenses. And if you read the 300D review, you can also know what lens mount it uses.
Probably TS do not get a manual from this older model of cam.
Any Canon lens can mount on crop sensor cam, but not on Full frame cam. 300D is a crop sensor.
Read the review in DPreview should help you understand more.
