Can you be more specific about your MySQL setup? Does your question pertain to configuring rails to talk to MySQL database (the settings in 'database.yml'.) or are you talking about how to get rails to use lagacy tables that following a naming scheme different than rails assumes? I haven't yet deployed rails with apache...have been doing all my testing with webrick, I'm just not at that point yet.
If you are just trying to demo or learn rails, you can get rid of the separately installed Apache/MySQL (unless these are installed for other reasons). This just adds layers of complexity you don't need while trying to get your bearings in rails. If for whatever reasons you want to stick with the separately installed MySQL/Apache then manually install rails as instructed at http://rubyonrails.org/down and follow the configuration instructions for getting rails working with MySQL/Apache. You should treat it as an either/or/but-not-both situation...that is, either go with InstantRails(and the bundled MySQL and Apache) or manually install Rails/MySQL/Apache separately but don't try to combine the two solutions. It sounds like you are at the early stages of RoR learning. By using the InstantRails solution, you can skip configuration headaches and just focus on using/learning rails. By doing things manually, you introduce layers of complexity to the learning process. I'm still learning rails and I have deliberately put off trying to configure rails with Apache because 1) I'm still a good ways off from being production ready and 2) I don't need the stress/distraction of troubleshooting additional configuration stuff while I'm still trying to learn how to write my own methods.
does this help? or did you get a better idea of what you're trying to accomplish in the meantime? let me know.
john-scott