Use a cage with a plasctic bottem for easy cleaning.
NEVER use plastic tubs or Aquariums that have poor ventilation.
Use a cage with a wire top.
NEVER keep a guinea pig out side.
Keep them in a draft free place.
Suggested Cages
About 7 sq ft is the minimum for 1-2 guinea pigs. The MARCHIORO (Tommy K) Mammal Cage (large - 40x21x20.5) is a good cage and for 2-3 guineas I recommend MARCHIORO (Tommy K) Mammal Cage (extra large - 47.25x23x22). These cages are also available a Pet Supplies Plus.
www.CavyCages.com Has cages that are larger and come in a variety of colors.