VC1.m:
-(void) yourMethod { ...}
VC2.m
YOURViewController * vc2 = [[YOURViewController alloc]init];[vc yourMethod];[vc release];
Make sure to import your YOURViewController
in your other view .m fileSomething like that should work.
Or if you're having problems, try this tutorial here:
Tutorial on How-To Pass Data Between Two View Controllers
Hope this helps :)