The reported price tag of $65 million includes the Sabres, Buffalo Bandits of the National Lacrosse League and the rights to HSBC Arena.
Hamister and Berman will need a final nod from the NHL's Board of Governors and likely approval from Bankruptcy Court. The closing should take place in the first quarter of 2003.
The Sabres, who joined the league in 1970, have been run by the NHL since June, after John Rigas and two sons were indicted on fraud charges following the collapse of Adelphia Communications.
On Thursday, Rigas called Hamister to congratulate him. The former owner is expected to have a role in bankruptcy proceedings, according to NHL Commissioner Gary Bettman, who characterized Rigas' involvement as "cooperative."
Rigas has been accused of stealing hundreds of millions of dollars from Adelphia, leaving the team in financial ruin and despair. That began to change Thursday, when Hamister explained why he and Berman were there.
"We love Buffalo, we love the Sabres and we love the fans who buys the tickets, stomp their feet in the arena and cheer for the players who work their hearts out every time they put on a Sabres uniform," he said.
"To (the fans) we have one simple message -- we too are going to work our hearts out with loyalty and integrity to make the Sabres a team that will play in Buffalo, stay in Buffalo and succeed in Buffalo.
"This team will be run by a Buffalo-born and -bred management team that will keep the Sabres in Buffalo where they belong and give this organziation the players, the support that they need to win both on and off the ice."