Cool SMS Sites (top 10 )

MessagingYou
Send a text message to virtually any cellular phone in the United States with MessagingYou! Freeware application for FREE SMS in the U.S. All major carriers.

Software download. Not sure if sms that are sent are free more...

SMS Everywhere
Send text messages (SMS) to cell phones

There is NO LIMIT to how many messages you send once you register, apparently. Otherwise, you can send 2 messages more...

O2
Send free SMS by registering with O2 (even if you're not an O2 customer). Just register your UK details

You can top up your text messages by purchasing 30 sms for £1.50. O2 also offers free wallpapers and free more...

TextMeFree.com & Fonetastic
Send free text messages using TextMeFree.com's free uk sms service (operated by Fonetastic). Includes 2 free logo credits, and address book. United Kingdom (UK) mobile phones only

Service is free and more or less reliable. Fonetastic free sms has been around for many years. Watch out for more...

sms.BizHat.com
Send Free SMS to Indian mobile phones

Not all networks included, apparently more...