You could also try Netbeans 6 which includes good support for Rails as well as Subversion.
Another nice thing about rails are the myriad of plugins and code generators that you can get to do a lot of the "framwork" coding for you.
After spending a while (my learning curve) writing a portal, I cam across "Goldberg"
http://goldberg.240gl.org/. This looks cool, but I have not had time to try it yet. Now I've written my own portal I'll probably stick with it because I know how it works but for someone starting out Goldberg may give you the head-start...
Another useful thing I've found is ActiveScaffold
http://activescaffold.com/ which also looks very useful.