Heat a large nonstick skillet over medium-high heat.
Add kielbasa, and cook 2 minutes on each side or until browned.
Remove from pan, and keep warm.
Add oil to pan.
Add bell peppers, garlic, and onion; saut 7 minutes or until lightly browned.
Place sausage on top of vegetable mixture, and add beer. Bring to a boil; cover, reduce heat, and simmer 15 minutes or until vegetables are tender. Increase heat to medium-high, and cook, uncovered, 3 minutes or until liquid evaporates.