I'm not a fan of Facebook's messaging system, but for many it's fast replacing email.
This maybe in part due to the convenience offered by Facebook by aggregating all of a user's social interactions online in one place. Another possible reason being that Facebook's system goes someway to eliminating spam since you have much greater control over who can and can not send you messages. It's not surprising then to see a company targeting this trend by offering a "push" solution for Facebook messaging on a cellphone.
Blue Whale Systems' BlueWhaleMail app now includes Facebook functionality, reports ReadWriteWeb. Think Blackberry meets Facebook as your friends' status updates, wall posts, and news items are automatically pushed to your cellphone. In return you can also send pokes, create wall posts, and email messages.
BlueWhaleMail free to download and is ad-supported.