iTwitter unexpectedly beat out Twittelator, Tweetie, Twitterrific, Tweetdeck, Twitterfon and all the other major iPhone Twitter apps to become the first true Push-enabled Twitter client on iPhone.

iTwitter pushes mentions and direct messages. However, there is a catch and it’s a big one. Push notifications are only received if the other person is using iTwitter too.

We were impressed by solid chat application IM+ debuting its 3.1 version last week with the ability to push Twitter no matter what app the other person used. There was a problem though because it was a chat application delivering the tweets, not a dedicated Twitter app. IM+ is just not meant for regular Twitter use. You had to try and ignore the notification or quit IM+ to get to your Twitter client of choice.

iTwitter, on the other hand, is a full-fledged Twitter client that debuts at version 1.0 virtually fully featured.

It might not match the power of Twittelator Pro (who can?), but it gives most of the other clients a run for their money when it comes to usability and features. It supports multiple accounts, groups, searching, nearby tweets, favorites and more of what you would expect.

Hopefully you can still snag it for free. The app was advertised to cost $3.99. I linked it up at the top of the article.

While it is certainly a major drawback that it won’t push all mentions or direct messages, I could see iTwitter gaining an enormous amount of traction in a short amount of time, especially if it’s free. Overnight we could see a seismic shift to the iPhone Twitter app landscape just from all the people wanting to use Push Notifications.

I don’t think it can be understated. Push tweets are a really big deal and iTwitter gets first crack at them. I know numerous people who will actually start using Twitter regularly if they receive mentions from friends without actually having to open the app. People always talk about the true power of Twitter being real-time. It’s not real-time until you receive an instantaneous push notification.

That happened for me at about 2:40 a.m. PST when I got a mention of @appleiphoneapps from @saeedk786 telling me iTwitter was working now. Then I received a few more and they were as instantaneous as an instant message or a text message.

I thought about going back to bed but I couldn’t let you all go about your day without at least alerting you to the fact this app exists and it’s available free at the time of this writing. Hopefully it stays that way.

Check it out and let us know what you think about it in the comments. Better yet, send me a Push Notification @appleiphoneapps or my personal account @hamiltonian04.

Personally, I see the iTwitter to iTwitter limitation not so much as a drawback but one heck of a smart business plan. They’ll convert tens if not hundreds of thousands of Twitter users in less than a day to their app. Hopefully Twitter, Apple, AT&T and iTwitter can handle the stress.