West Indies Soul isn't actually Jamaican - I think the owner is from Grenada or Trinidad - but they have dishes I think of as Jamaican: patties, jerk chicken, rice & peas, and a great cabbage-and-carrots side dish. Not sure if they have many vegetarian options, but if you eat fish, their red snapper dish is wonderful. There are two locations - one in St. Paul, and one at the Midtown Global Market.
Jamaica, Jamaica is in S. Mpls. I've only been here once, but really liked the food. But I didn't notice whether they had a vegetarian-friendly menu - sorry!
Jamaica Jamaica Restaurant
3765 Bloomington Ave, Minneapolis
Note: City Pages has a link to their menu, which includes Curried Veggies and Curried Tofu. Yay!
Marla's is a Caribbean place with an owner from Trinidad, so she cooks Indian food and "island" food. I think they have vegetarian options, but all I've ever had is the goat roti, which is yummy (it's probably obvious by now that I'm not a vegetarian...)
Check out this thread for more ideas: