I gave GRE two months back. Although my score in verbal (550/800) and quant. (800/800), i got 3.5/6 in essay section. Can anybody tell me whether this score is okie for getting admission for PhD in US ? Should i mention the Score when it come to PhD admission in Europe?

I think your scores are Ok and they should get you into a good college in the USA.
NO the Europeans aren't that impertinent to ask so many scores from us students.

I'm from germany and did not do any kind of GRE- and was never asked for one either. My initial interview was over the phone and if that goes well I don't think the score is so vital.

Thanks for the information. I find GRE to be compulsory for north america universities. In europe it not required in many universities.

it depends on the program. your quant score is perfect, verbal is on the low end for grad school. same for the essay section. the more quantitative the ph.d program is, the less the low scores will matter