Swype comes pre-installed on a number of devices, but there are many that were in existence before that started, and ... it doesn't come installed on the stock Android Nexus S (although Pulse and NoLock do, surprisingly). However, it appears the beta is open again. Grab it while you can.
Swype allows you to "swipe your finger" from key to key and draw a word. If it can't determine what the word is it will give you a list of words to pick from. Unfortunately, if you try typing with it and assume it is correct, you may end up what some call "Swype-isms" ... mistakes because it predicted the wrong word.
Swype is pleased to offer an (updated) Android Beta!Here are the details:
In English, Spanish, Italian, Portuguese, German, and introducing French and an early, *UNSTABLE* preview release of Chinese Pinyin
Now includes support for Double-Tap-to-Edit, Cursor Restore, and Voice-to-Text (requires Google Voice Search be included in your system firmware)
HVGA, WVGA, and WVGA854 Resolutions - don't worry we'll detect this automatically. Sorry, no QVGA
Limited End User Support - mostly via our forum
If your phone came pre-installed with Swype, DO NOT download this beta (it won't work)
To get Swype, you simply register on the site with an email address, and they'll send you a link to download. Since this is a sideload operation, if you have AT&T, you'll have to use one of the workarounds to sideload on your device.
It's unclear if the beta will close again. To be safe, go for it as quickly as possible.