I'm wondering about Slashcode (http://www.slashcode.com). Would it actually work in a shared hosting environment? What about its PHP counterparts?

Slashcode should work in a shared hosting environment... but for starters you'd need to have your host install it's required parts (slash, perl modules and mod_perl which some hosts will not offer). Slashcode is also known to be a big memory user which might lead some hosts to not allow this on a shared environment. The bottom line is whether or not your host will be willing to allow you to run it in their shared environment, not to hard to just ask them if you are really considering it. There are also some hosts out there that specialize in hosting slash sites.. you can find links to them at the slashcode website.

From what I know (and about this topic, it's not much)... Slashcode is meant for really heavy duty websites and isn't really recommended for a beginner (just means you should know your stuff on Perl and the basics of being a webmaster). PHP-Nuke and PostNuke on the other hand are good alternatives... you can install these on your own without having to ask your host for much help.. if any, and they are easy to run. Something to consider when running these scripts is they can become resource intensive depending on the size of your user base... so you might even run into trouble with your host because of that.. but not likely.