If it's listed as a regular service at the resort, it means there is someone available who can make reservations for guests at area restaurants & shows, answer questions about what there is to do in the area, obtain tickets (sometimes at a discount, other times at a higher price, due to commission). The concierge can assist you in making all kinds of vacation plans & arrangements.
If it's listed as a classification of a room type, then it means the guests in that room receive special attention and services not normally afforded to all hotel guests there. This may include anything from extra attentive concierge services, to complimentary happy hour or evening beverages, snacks, desserts, to full butler services. It varies by the hotel and the level of concierge services they provide to their concierge guests. HTH.