A Wala is a wiki that has been changed to be more friendly to casual readers and contributors. Editing the complete text of any page can be intimidating to many, especially when all they want to do is add a comment to a page. So, a Wala is a wiki with two main changes:
Wala is written in Perl, and may be easily used in conjunction with other Perl scripts. It should run on most Linux or Unix web servers which support CGI. It will probably work with your web host.
Good question. A wiki is a website where anyone can change any page at any time. The entire website can be completely rewritten by anyone. This means that any errors can immediately be fixed by anyone who happens to see those errors.
Moreover, a wiki uses a very simple markup syntax. Instead of using HTML's sometimes confusing tags (like <p> and </p>), wikis use simple characters like ''this'' for emphasis or '''this''' for bold.
(And most wikis keep backups of all pages, so that vandalism can be fixed.)
Glad you asked: walawiki.org/source.
If you have Subversion installed, you can check out a copy of both branches with
svn co http://walawiki.org/source
Versioned tarballs and other paraphernalia shortly.