Currently I am fighting with Joomla and XAMPP installation and trying to make it to work so I would like to post a question on the main Superuser site but searching for Joomla on the Superuser I get bunch of questions which were closed as being off topic. Is asking about Joomla problems considered to be off topic?
Thanks for asking before posting your question. I have discussed this with several other moderators, and we think the best fit would be on Server Fault, because you are installing a web package on a server. Without knowing the specifics of your question, we can't say for certain though. Make sure to give Server Fault's FAQ first to make sure that your question would fit within their guidelines. If you have any more questions, please comment on this post and we will do our best to help you.
Sounds like a job for Stack Overflow!
You're installing and setting up a CMS or a framework, which Joomla! can either be. On top of that, you're trying to finagle it with XAMPP. Both of these are often seen on the Stack Overflow mothership.
But it does largely depend on what the question is.