Generously season shanks with salt and pepper. In large skillet, heat oil over high heat. Brown shanks on all sides until golden brown, about 15 minutes. Remove from pan and place in a 13 x 9-inch baking pan. Pour out liquid from pan.
In same skillet, combine garlic, carrots, onion and fennel; sauté for 6 to 8 minutes to lightly brown, stirring occasionally. Mix in beer or broth, tomatoes and juice, chicken broth, thyme and bay leaves. Bring to a boil. Pour over shanks. Braise in 375°F oven for 2-1/2 hours. Baste shanks with sauce and turn them over every 45 minutes. Serve lamb in large, low-sided soup bowls with broth and vegetables.
*24 ounces of fat-free chicken broth may be substituted.