During their press conference earlier today, Twitter CEO Dick Costolo and co-founder Jack Dorsey revealed a brand new Twitter.com and official app redesign, which took the spotlight.

However, some smaller bits of news came out of the conference as well: specifically, a firm(ish) timeline for when we can expect to see self-serve ads available to marketers.

OK, so “early next year” might not be that firm, but for a company that doesn’t like to give out dates for anything, it’s as specific as we’re going to get.

Reuters is reporting that Costolo and Dorsey said that the new self-serve ad product will be available to marketers in early 2012.

As we reported earlier this month, Twitter has been experimenting with rolling out self-serve ads to a small group of select partners already.

The platform allows advertisers to purchase products like Promoted Tweets and Promoted Accounts on a cost-per-engagement or cost-per-follower basis. Prices for ads on Twitter are said to range from $2.50 to $4 for every follower associated with a Promoted Account, and $0.75 to $2.50 for every engagement (being a click, favorite, retweet or @reply) associated with a Promoted Tweet.

As they’re already experimenting pretty seriously, news that marketers will have access to the platform “early next year” could mean one of two things: that anyone who is interested in purchasing an ad on Twitter will be able to do so through the self-serve platform, similar to Facebook ads, or that all 2,400 advertising partners will have access and the rest of us will have to wait.