Functionality & Service
There are several other services on the iPhone which can be used for free texting, such as Google Voice. Another commonly used app is Textfree Unlimited. While these applications do offer free domestic texting on the iPhone, they do not offer service comparable to HeyWire.
The HeyWire service is quite simple to use. Signing up for an account is done upon first run of the application and you will be assigned a phone number. Phone numbers are limited to a very small area and, therefore, you will likely not be able to find a local number. This is not a big deal since the service is free.
Sending text messages to domestic numbers is just as you would expect. Simply enter the phone number or select the contact from your iPhone's address book and enter your message. Press send and your friend receives the text message as if it was sent to a regular phone. Your friends can simply text the number back and you will receive the message.
International text messaging is equally easy. Simply enter ~ezentity_quot+ezentity_quot~ and the country code, followed by the full phone number. Enter the message and press send. HeyWire supports most major cell phone carriers in most countries. Your friend will receive the text message from your USA based number. They will have to reply back to your USA number which may cost them some money, but it will always be free for you. If they happen to have a smart phone with Internet connectivity, they could consider using HeyWire as well to create completely free texting back to friends in the USA.
Messages are delivered instantly or nearly instantly. After extensive usage, no messages have been lost or failed to send, that includes several days worth the messages to international destinations such as El Salvador. Overall the service is excellent and the messages get to where they should in a timely fashion, just as if they were sent from a regular cell phone.