Here is a SMS guide that contain some free SMS utilities to help you with your day-to-day tasks.: 
AreMySitesUp:
A free service that warns you when your site goes down. It lets you check up to 20 sites. Site checks are performed 25 times per day. Premium Service is priced $75/year that lets you check up to 60 sites.
Notifixio-us:
This free service lets you monitor your favorite websites for updates. As soon as a new post is up on a site, Notifixious will send you an update on SMS, IM or email. Pretty cool!
StuffAlert:
Similar to notifixio-us but for ebay. It alerts you when items you want are listed on eBay.
TextMe2Day
Send free SMS worldwide from the comfort of your computer. No registration required.
Cherple
Send and receive SMS from your computer. Currently this service is available in US only.
UmbrellaToday
Get SMS alerts when there is a chance of rain in your area. Currently available for US only.
rmbrME
Create a virtual business card and then instantly share it via SMS.
YouArchiveIt
Lets you backup your iPhone SMS messages online.
Watch My Cell
This app periodically check for your cell phone balance and alerts – via SMS – you when it’s close to going over.
Hope you enjoyed our free sms utilities guide. Let me know through the comments below if you know about other such sites.
Ankur Jain is a Software Engineer in Test Automation. After a 5 years stint with Accenture and Oracle, he started his eLearning company. A long-time blogger and proud owner of the "Learn" series of websites. 
Hi, nice post. I have been pondering this issue,so thanks for posting. I’ll definitely be subscribing to your site.
Great tools. I’ve used Cherple and it’s excellent for carrying on a real text conversation between the PC and mobile via SMS. It’s the only one I’ve found that sends AND receives SMS from the PC. The others seem to be one-way only.
Thanks Brad and Mike. Glad you liked them.
Thanks for the great list of SMS tools. The “AreAllMySitesUp” will be getting used for sure.
Keep up the good work!