Need help with dmg and exe files!

[fitzer]

If someone can help me on this I'd be most appreciative! I see some of the files I'd like to grab (and share) are dmg. I also see exe and another or so that I'm unfamiliar with. I'm on a Mac and in the process of upgrading to Panther. What is the procedure with a dmg and/or a exe file? How do I open it or convert it to a usable/installable file. .Sit files and zip files I'm familiar with...Just unstuff and open or install. I also have seen toast files. I use toast to burn cd's but don't know much more about toasts functionality. Thanks in advance for any help you might have to offer.