If you have php code that needs to be converted to ruby/rails there are a few starting points
hyperpolyglot should be your homepage:
On the ruby site there is a nice intro on Similarities and Differences.
From Rails for Php Programmers i used this pdf PHP to Rails Reference (extract)
on the translating php cookies and session (params for post/get ...)
Also the PHP to Ruby reference is very good
Ps: main site http://railsforphp.com/ seems to be down at the moment but i guess you can fork and build the reference yourself