Whats the biggest cup size (for women), and how are the sizes arranged?

Standard bra. Sizes are arranged alphabetically, but with different systems in the us, uk, and european countries, especially once you get past d cup. Although victoria' secret doesn't sell anything past a dd / ddd, other companies sell bras with cup sizes that are much larger, but still look attractive. Try freya, curvy kate, or panache, for starters.
AA to J. From smallest to largest cup size: aa, a, b, c, d, dd or e, ddd or f, g, h, i, j.