Urgent about mobile fares and Blackberry (Montevideo)

Hello, I'll be moving to Montevideo for business very very soon, I have a Blackberry but I can't use it in Uruguay with my Italian number, I need to buy a local mobile nr and I need to know something about fares. Which operator is the best one to use with my BB? Are there prepaid services? I hope somebody here can give me more details.
Thanks so much guys! Looking forward to meet you in Uruguay! :)
Alessandra