as a note on the rsa/cambrdige thing. no it is not necessary to have. i actually got the certification but never once have i been asked for any certifictaions and found tons of work. i don´t think it´s necessary at all. i kind of think i wasted my money and time on it cause i can get work anywhere without it. but i guess it´s all a personal choice and some people feel better if theyhave some certificate.