The old standard is NCSA Mosaic. New on the market is Microsoft's Internet Explorer. Bear in mind, though, that these last two won't work with lots of Websites, since most of them are designed to utilize the superior features of Netscape Navigator. Though these are not the only ones on the market, they account for the majority. About the only other difference is the address you send it to.
Mailing lists are a kind of e-mail club made up of people who want to discuss a common interest.
Here's how it works. Let's say you are obsessed with Victorian hats and want to correspond with other people who share your interest. The regular kind is just textual messages. The binary newsgroups contain pictures, sounds, program updates, etc., which you can download and use. Another important difference between mailing lists and newsgroups is that, while anyone with e-mail access can join any mailing list that is open to the public, your ISP decides which newsgroups you have access to.