The project home page includes a screenshot, but you can also visit a project hosted on a public facing installation and can click around. There are nice diff pages and you can also get a blame report.
The project is still very young, but looks promising.
GitPrep is written in Perl and it is very easy to install, even on a shared host. It can run its own web server, use any web server supporting PSGI/Plack, and it can even run in CGI mode for those shared hosts.