I know somebody on here used it successfully in mead.
As to beer, I dunno. I'm not sure what style of beer I think would be good with a rosemary flavor, but even in my cooking I'm much better with spices than with herbs.
rosemary was an essential part of the 'ale grout'-a brewer's bouquet of herbs used to flavor ale in Europe before the introduction of hops. Use 1 1/2 ounces of fresh leaves late in the boil for flavor and aroma. Or use for dry hopping in fermenter to add a stronger piney scent to your beer.