Sippy cups for all ages and occassions. Glass or stainless steel, soft silicone spout or hard BPA-free spout.
Some babies will have an easer time making the switch to a sippy cup that has a soft, nipple like, spout rather than a hard spout. Sippy cups with easy to grip handles are also another favorite among babies making the switch to a sippy cup. After your baby is comforatable with a sippy and a bit older, taking a sippy with a hard spout of even a straw bottle sippy should come naturally.
A word of caution about leak Proof sippy cups, while they are a great invention as far as avoiding spills, they can make "sippying" very difficult for your child and the extra suction needed to suck the fluid out of the sippy cup can result in ear infections.