This report has now been confirmed by the Buffalo Bills and the NFL.
The 2010 NFL schedule is not slated to be released until later tonight, but the NFL.com Schedule Interactive page for the Buffalo Bills indicates that the Bills will host the Chicago Bears in Toronto in the 2010 regular season. Or, rather, it did over the noon hour; it's since been changed back to read Orchard Park, NY.
Obviously, no date has been announced for that matchup if it exists, though November 7 has been mentioned as a possibility.
Buffalo has previously hosted the Miami Dolphins and New York Jets at the Rogers Centre in Toronto, losing both matchups. Chicago is coming off of a disappointing 7-9 finish with new quarterback Jay Cutler, but the team made major waves at the beginning of free agency, signing end Julius Peppers and running back Chester Taylor on the opening day of the signing period.
Buffalo's complete schedule will be released at 7PM this evening. We'll have it up for you as soon as it's made public. Keep in mind that this report is not definitive.