picture-14Until now in Apple’s App Store, an all-in-one IM client with push notification was something you had to pay for, but eBuddy‘s changing that.

The app is the first free all-in-one IM client to notify users of incoming chats, even when the program window is closed. eBuddy works with AIM, Facebook Chat, ICQ, Gtalk, Yahoo and MSN Windows Live Messenger, pulling all the services into one interface. An icon next to each of the buddies you’re chatting with helps you remember what program they’re on, while chat windows remain uniform across all services.

Nimbuzz and Fring, two similar services that also support VoIP, would be wise to follow suit with push notification, as it’s the strongest feature eBuddy has that they don’t.

Paid all-in-one messaging services were quick to support the feature. There’s Beejive ($10), Agile ($10) and and IM+ ($5). The last example offers a free version that doesn’t include push notification.

Apple introduced push notification, which pings users with updates even when they’re not using a given program, with the iPhone’s 3.0 OS. For up to 30 minutes after closing eBuddy, users are notified when a new message comes in. This is a clever use of the service because pop-up messages are a natural extension of the program rather than an intrusion.

Other perks to eBuddy include automatic reconnection if the iPhone’s signal drops and the ability to buzz buddies by shaking the smartphone, but it lacks some of the features of its paid competitors, such as Twitter support.

So far, eBuddy is faring well on the App Store, ranking as the top free social networking application in 21 countries, according to Distimo. Before launch eBuddy’s Lite version for PC users netted 2 million downloads. I’ve reached out to eBuddy for details on monetization efforts and post-launch plans and will update when I get a response.

eBuddy, formerly called e-Messenger, is based in Amsterdam with offices in London and San Francisco. It’s privately held and backed by Prime Technology Ventures and Lowland Capital Partners.