Google is shaping Gmail into the ultimate communications hub. Today, the company announced that United States users will be able to make and receive calls within Gmail, providing they install the company's voice and video plug-in.

Users could already call and video chat with other Gmail users, but the new features allow them to call landlines and cellphones. Google says that calls to phones within the U.S. and Canada will be free for at least the rest of the year, and calls to many other countries will cost 2 cents a minute.

Google writes:

We've been testing this feature internally and have found it to be useful in a lot of situations, ranging from making a quick call to a restaurant to placing a call when you're in an area with bad reception.

Google previously made a foray in Gmail-to-phone communication with an experimental feature that allowed users to send text messages to phones. It was a smooth, impressive step toward blurring the lines between the different forms of communication that people use on a daily basis. However, abuse of the system (including an iPhone app that piggybacked on it in order to provide users with free text messages) pushed Google to limit its functionality.

By adding the ability to call phones, Google is pushing to set Gmail apart from other webmail services, and it probably means other communications systems will be centralized within that interface.

I've sent more text messages today than ever before in a single 24-hour period. Admittedly, "more than ever" actually means about 10 but, thanks to Google, this may only be the beginning.

I'm just a few years too old to be truly fluent in text messages, as far as I can tell. I don't like triple-typing, I don't own a smart-phone with a nice keypad, and the predictive text on my Motorola leaves a lot to be desired. So, unless I'm in a library, I am likely to respond to a text with a phone call. It just seems easier. On the other hand, I am chained to the computer as only a geek can be, and am available by instant message easily 16 hours out of the day.

Most of my family is not this way. They check their e-mail accounts once a week so there's no way to send them a quick message. That's why I was thrilled to see that GoogleLabs now lets me send text messages from Gmail and Gtalk.

Google Labs has a lot of neat little widgets, some silly, and some useful. For example, Mail Goggles is mean to stop potentially embarrassing late-night drunken e-mails by forcing users to solve math problems before the "send" button will activate. Surely, this is mostly a joke.

Forgotten Attachment Detector, on the other hand, which alerts you when it suspects you may have neglected to attach a file, could have saved me much agony in the past. Neat as these toys are, text messaging in chat made me literally write home.

It's not the first time a company has tried to unify communications this way. Not long ago, I wrote a story about similar technology called VoxOx. But Google has done things beautifully, in just the way that has made their webmail, feed reader, search, and all the rest so popular.

To send a text message from Gmail, I type in the phone number and click "Send SMS." When my friend replies to the message, it pops up in Gmail, or on Gtalk, and I can respond as if chatting through IM. I've already used it to plan my evening tonight.

I sometimes get nervous about how many of Google's services I use, but when they're this good, how can I help myself?