How to make my kid drink milk in a glass?

he is 2 and 1/2 yrs old and he likes drinking milk,but in bottle.everyone is advising to make him leave the bottle,but he is not showing any inclination to drink in a glass.it seems he likes to suck.i m afraid that way he will stop drinking milk which i do not want.i hv tried various flavours but he just doesnt want milk in glass.can anyone help?