I have a 5 year american visa.. (b1/b2 r-type).. Multiple entry. Since I got it in September 2008 I haven't being able to travel with it . But I just got my leave for 3 months and wanted to go and visit my brother in the states.. what do I do

Just buy a ticket and go... have fun!!

So you mean.. I can just leave without anyone immigration officer trying to worry me when I get there..