Each time I start my Rails 2.3.8 webapp under RubyMine, it's using a different port. This drives me mad, since I've to change the URL in the browser each time I want to test something. I'm unable to find any configuration option to change that. Anyone?
This may not help because I'm using RubyMine 3, however, there is a dropdown menu in my toolbar for selecting the different development environments (e.g. production, development).
The dropdown menu is to the left of the green "Run" triangle. If you click on the list one of the options is "Edit Configurations" - this pops open a window that has server port configuration settings in it.
Hope this is the same in your version of RubyMine!