How do you do this? Ive seen alot of protected maps, and i was wondering how to do this.

You use a third party program like this: http://www.staredit.net/files/12/ to protect your maps

Some of the protectors that were on maplantis were great protectors. http://www.staredit.net/maplantis/index.php?sid=48bec6297c;wiki=5#wiki_5

OS Map and TinyMap are by far the best protectors, as they are really only meant to compress, so they make your map as small as possible, protecting it as a side-effect.