We have created an easy to use installer for Mantis that also installs and configures Apache, MySQL and PHP. The idea is to have everything up and running by the time you click 'finish' so that you don't have to do any manual configuration. Currently we have Windows and Linux versions, with OS X and Solaris planned.
Our goal is to make open source applications as easy to use as possible (we have installers for other projects as well).
If this is something that interests you, please check it out and let us know what you think. We plan on updating new versions based on user feedback in the BitNami forums at http://www.bitnami.org/forums (be kind, this is an early release
)http://bitnami.org/stacks/#mantis
The installer is open source (Apache 2.0 license)
Best regards
Antonio