Celebrities like P-Diddy and Ashton Kutcher aren't lugging laptops around when they go to parties and nightclubs, but they're always updating Twitter. How do they do it? The secret is: there's a Twitter client for just about every mobile platform. Whether you use Gravity on your Nokia, Twitterific on your iPhone, UberTwitter on your Blackberry, or just visit the Twitter mobile site, you have tons of options available to make sure all of your friends and followers know what you're up to, and read what they're doing.

Much like Twitter, Facebook is a great way to stay in touch with people and see what they're up to at any given moment. There are several third-party Facebook apps for just about every mobile phone, and some phones even come with Facebook apps already installed. If you don't have one or can't find one, give Facebook's mobile site a try -- you still get all of the features and can read updates from all of your friends, just without the hassle of finding a computer.

If you're looking for a social network built with mobility in mind, head over to Jaiku. Much like Twitter or Facebook, you can post short messages to your account to let people know what you're up to, and read all about what everyone else is up to as well. Best of all, there are downloads for just about every mobile platform to help you post and read updates, if you don't want to use the mobile Web version.

You've got a phone that can take short video, and you just recorded something you want to share with everyone. Qik can make sure your mobile masterpiece is seen by all of your Twitter and Facebook friends. All you have to do is visit Qik from your mobile device and the service takes care of the rest, even recording your video and uploading it to the Web. If you let it, Qik will even post your video so your friends can watch live, as you're streaming.

If you have accounts for multiple social networks, staying on top of them all is a pretty daunting task. That's where Shozu comes in. Shozu pulls your friends' updates, video, photos, and other content from multiple social networks like Twitter, Facebook, Bebo, YouTube, and Flickr and puts it together into one easy to follow stream of activity that you can browse from your mobile device. You don't have to settle for reading either, Shozu also allows you to post to all of those networks right from your phone, and has special apps for Nokia devices and other Symbian phones, the iPhone, Blackberry devices, and Windows Mobile phones.