
1- AudioBoo

AudioBoo is another useful utility for sending audio tweets. They have also launched iPhone and Android apps for sending audio tweets using AudioBoo however you can make audio tweets using their online service as well. Simply, sign in using twitter OAuth, choose a username for AudioBoo account and record a tweet (for maximum 5 minutes). Listen your recording, once happy with it, give it a title and it will be added in "Your Boos" section of the website. From "Your Boos" section, you can share it on Facebook, Twitter or get the embed code also. In your tweet, it will appear as a link which will look like http://boo.fm/b1FD3
Website: http://audioboo.fm/2- Chirbit

Its another free service however it does not support OAuth as its not designed for twitter only. However you can create a free account with them within few seconds. After creating account and signing in your account, record your message (maximum of 2 minutes), listen recording, once happy, choose a category for your recording. Save your recording. Now click on cog icon on your recording which will display you options to share this recording on Facebook or on twitter. This will display a link in your tweet like http://chirb.it/7HAsb
Website: http://www.chirbit.com/3- TVider.com

Tvider is a FREE service specially built for twitter and micro blogging. It also gives facility to make audio tweets however apart from audio tweeting, you can also make video tweets with TVider. It gives very simple interface to record your video tweets using Webcam or audio tweets using mic. You can also upload a recording file from your system. Have a look at your recording and finally tweet it.
Website: http://www.tvider.com
4- TweetMic

TweetMic is a simple and intuitive Twitter client app for the iPhone that allows you to make high-quality audio recordings or "Tweetcasts" and publish them directly to Twitter. There is no limit to how much you can record and you don't need to sign up for any additional service to start using TweetMic. Following are features of TweetMic.
- Incredibly simple and intuitive interface
- Quickly record audio and publish to Twitter
- Review your recordings before publishing
- Easily overwrite old recordings by hitting "record" again
- Create unique and engaging Tweetcasts in no time
- Ultra high recording sound quality
- Unlimited recording time
- Uses your existing Twitter account, no additional signup
- Navigate and listen to your published audio tweets
- Your tweets stay live unless you delete them
- Easy management of your audio tweets at tweetmic.com