Seven cities vie for two new expansion franchises - ESPN
Atlanta, Miami, Portland and St Louis will aim to become the United States' latest representatives, while Montreal, Ottawa and Vancouver are seeking to give Toronto FC competition in the Canadian market.
This round of applications is for teams 17 and 18 and a decision is expected late this year or the early part of next year, prior to the start of the 2009 MLS regular season in late March.
There are currently 14 teams in the MLS, with Seattle Sounders joining the League in 2009 and a Philadelphia expansion team set to debut in 2010.
The seven competing cities come with some heavyweight financial backing.
Miami's bid is being spearheaded by Barcelona and prominent Hispanic businessman Marcelo Claure, while Montreal's tilt for a MLS team is being headed by the Saputo and Gillett families - George Gillett Jr being the co-owner of Barclays Premier League club Liverpool.
Arthur Blank, owner of National Football League team Atlanta Falcons, is heading the city's bid, while basketball superstar Steve Nash is one of three men behind Vancouver's effort.
MLS president Mark Abbott stated the league had conducted a great deal of analysis behind their expansion plans and added it would take a three-pronged approach to selecting the successful two cities.
"The formal bidding process begins today with the submission of bids from interested groups," he told the MLS website.
"We will then review these bids at the league office and with the league's expansion committee.
"We will then meet with each of the cities, each ownership group and leaders from the community and then we will make a formal recommendation to the board for their approval.
"There are three criteria that we are going to be looking at. The first is the strength of the ownership group and that's always been a hallmark of the league. The second will be the plan for the stadium because these facilities are very important for the success of our teams.
"Third, we're going to look at market attributes, such as the size of the market, the appetite for soccer and what the corporate community in the market is saying about soccer."
He added: "We have done a great deal of analysis and have concluded that we can add two more teams in 2009 and 2010 and then two more in the round after that."