tinywords.com - about mobile phone SMS messages: "
ProviderMessage serviceCostMaximum message length *What's my address?For more information
AT&T WirelessText MessagingZero to $9.99 monthly fee, depending on plan; $0.10 per message beyond plan limits.110 characters[10-digit phone number] @mobile.att.net Example: 9055556543 @mobile.att.net more info pricing

CingularInteractive MessagingZero to $9.99 per month depending on number of included messages; $0.10 per add'l message.150 characters[10-digit phone number] @mobile.mycingular.com Example: 4152221212 @mobile.mycingular.commore info pricing

Metrocallvarious pager servicesvaries depending on service80 to 200 characters, depending on subscription plan[10-digit pager number] @page.metrocall.com Example: 2125551212 @page.metrocall.commore info

NextelMobile Messaging, Online Messaging, or Two-Way Messaging$0.10 per message, or 100 messages for $3/month, 300 messages for $5, 1000 messages for $9140 characters[10-digit telephone number] @messaging.nextel.com Example: 7035551234 @messaging.nextel.commore info pricing

Sprint PCSWireless Web Messaging$1.99/mo for up to 30 messages ($0.25 each add'l), or $9.99/month for up to 200 messages ($0.10 each add'l)160 characters[10-digit phone number] @messaging.sprintpcs.com Example: 8155551234 @messaging.sprintpcs.commore info

T-Mobile (formerly Voicestream Wireless)2-Way Text Messaging$2.99 for 500 messages/month; included free in some calling plans140 characters[10-digit phone number] @tmomail.net Example: 4251234567 @tmomail.net more info

VerizonText Messaging$0.02/message; $2.99/100 messages100 characters[10-digit phone number] @vtext.com Example: 5552223333 @vtext.commore info"

Here is information I've looked for on many occasions...