I’ve been using PHP all along at Yahoo!, Zynga and Interviewstreet. While building hacks and pet projects, it was always python. Django for full sites and web.py for apis.
When we started, language choice was a hard decision. Only one of us knew ruby, PHP was never in the list of choices and python was an option.
We went ahead with Ruby. We built close to 5 prototypes with it. It was hard for the first one. Plenty of googling for every language keyword.
It really did help us when we had to iterate fast.
With that said, here are some places for you to get started on ruby.
It will take few days to be on speed, but worth the effort. If you are using PHP at your work, I’d recommend choosing Ruby for your pet projects. The biggest advantage that a language/framework can give you is ability to finish your project in a weekend from nothing. You can easily focus on your idea with available rubygems.
If you are sure that your project needs to operate on high-scale from day one, then probably rails is not a right choice.
More problems with Ruby/RoR:
But all this matters if people use your hack/product. If they use, you have a good problem to solve.