TwtQpon lets you create coupons for promoting your products or services and then post them in your Twitter feed as part of your. If you have products or services you want to promote to your Twitter followers, consider offering a small discount or incentive in the form of a coupon and take advantage of the viral / retweeting features of Twitter.  TwtQpon says: ” Enhance your social media marketing by offering discounted coupons to the Twitter-sphere!”

See a sample Twitter coupon here: http://twtqpon.com/cbm8zk

bit.ly allows users to shorten, share, and track links (URLs). Reducing the URL length makes sharing easier. bit.ly can be accessed through our website, bookmarklets and a robust and open API. bit.ly is also integrated into several popular third-party tools such as Tweetdeck. A more full list of third party tools can be found on the bit.ly blog. Unique user-level and aggregate links are created, allowing users to view complete, real-time traffic and referrer data, as well as location and metadata. Tracking stats are available after users shorten their long links with bit.ly by clicking on the “Info+” link on bit.ly, or just adding a “+” sign to the end of any bit.ly link (for example, http://bit.ly/n0og+).
Read full bit.ly article on NYTimes

HootSuite lets you manage your entire Twitter experience from one easy-to-use interface.

Creating an account is easy. Enter your Twitter username and password, and add a profile for each Twitter account you wish to manage. Got more than one tweeter per profile? Add multiple editors.

Then get going! Post live or pre-schedule tweets. Check stats and analytics right from the dashboard. Search Twitter for keyword information. Reply @ and Direct Message the folks in your conversation. Do all this and more from one fantastic interface.

Making an update on Ping.fm pushes the update to a number of different social websites at once. This allows individuals using multiple social networks to update their status only once, without having to update it in all their social mediums individually. Ping.fm groups services into three categories – status updates, blogs, and micro-blogs – and updates can be sent to each group separately.

Ping.fm was created with the intent of making it as easy as possible to post updates to multiple social networking sites simultaneously. The idea came about when creators were updating status messages with micro-blogging sites Twitter and Tumblr. The idea of posting the exact same information in two places seemed a bit tedious, so Ping.fm was born.

(from wikipedia.org)

PingFM says this about their services:

We post your messages wherever you want!
That’s right, we support over 40 social networking sites and we’re adding more all the time.
Between our straight forward posting methods and advanced custom triggers, we make it easy for you to post your messages exactly where you want them to go.