Mountain View, CA-based Meebo, the popular web-based IM service, has closed its big round of funding, we have learned, and the announcement is coming as soon as tonight or tomorrow. The round is expected to be in the $20 million or above range, though we haven’t been able to learn the exact details. Earlier reports pegged the funding raise at $25-$30 million round at a $200-$250 million valuation.