I have a nokia 7610, how can i tranfer some games or some applications to my brother's nokia 3660???

If the application doesn't have a built-in feature for sending itself to another phone, Your brother should buy them: http://www.allaboutsymbian.com/shop/

Note that all apps working on the 7610 (based on Series 60 2.1 and Symbian OS 7.0s) may not work on the older 3660 (Series 60 1.2s and Symbian OS 6.1).