In October, Google's e-mail client, Gmail, rolled out the ability for users to send text messages to friends' phones from their Web e-mail application. Shortly after the SMS capabilities were rolled out they were pulled, leaving a lot of Gmailers wondering what had happened. Today, however, Google is asking for a mulligan and adding the text messaging function back to Gmail through its Gmail Labs arm.

Adding the text messaging functionality to a Gmail account is easy: Click on the Google Labs icon, click on the "Labs" tab, scroll down to the text messaging functionality, and enable it. The functionality will then appear on the side of the window, near the contacts.

Google said the SMS messages will be delivered to the target phone "very quickly" after they are sent. But in typical Google fashion, the company is hedging on costs and privacy information.

The search engine giant notes that users should check with their carrier about the costs incurred in sending or receiving text, saying the costs will vary depending on the provider.

And privacy advocates should brush up on Google's Gmail Privacy Policy before joining the service. If you do plan on using the service, expect an invitation code to be sent to your mobile device from Google. It's also worth noting that Google said it will "store each phone number to make sure it is used to create a limited number of accounts."

Google said the number will be associated with the account to avoid unnecessary future verifications from other Google services. The search engine company also said it will never contact users with the number they provide without "express permission."

Currently, Gmail SMS messages are available to U.S.-based mobile phone numbers.