Update: The NHL lockout ended in July, with a six-year collective bargaining agreement. For the details see:
Junior-aged (under-20) players will be eligible to return to junior teams if there is no NHL hockey. Other players will join professional leagues in Europe, and a new World Hockey Association is hoping to recruit idle NHL veterans. Some players who go to Europe will commit to those teams for the entire hockey season, but most will have clauses in their contracts allowing them to return to the NHL if and when the NHL season begins.
The American Hockey League is not an option for most NHL players because the league's mandate is to develop new talent: teams are allowed no more than six players with over 260 games of pro hockey experience.
