You can find out more information about becoming a CA from wiki:
http://en.wikipedia.org/wiki/Institu...ngland_&_Wales
There is basically no difference between CA and CPA but CPAs are usually trained to be qualified in the U.S tax code and CAs in U.S have to apply for CPA license and have to pass an exam to be certified.
What I know fom people is that CA is way dificult than CPA so people who have repeatedly failed CA exams, pass the CPA exam in their first attempt....
Hope this helps...