Google Plus most definitely has this capability and it appears to have inherited it from the Google Chat capability that was integrated into Google Mail a long time ago. In fact, if your friends or colleagues are on Gmail and you're in G+, you can chat with them while waiting for them to get their invite to the G+ world!

This means that if you're at all used to Gchat, then you're ready to go. If not, well, it's pretty easy to figure out.

To get started, look on the lower left of your Google Plus home page. You should see something like this:

Click on "Chat with people on Google+" and after a moment or two your list of friends and colleagues will show up, with a green circle indicating they're available for text chat and a small green video camera icon indicating you can video chat with them (if you have video capabilities yourself):

One super nice capability of Google+ Chat is that you can limit who sees you as available for discussion by specifying which Circles get that information. Awesome!

To change this setting, move your cursor to the top right of the "chat" area and look for a subtle menu indicator button (a tiny downward pointing triangle) to appear. Then click on it:

Click on "Circles" to see just what a great availability feature they've added:

As you can see, I'm going to only advertise my availability for chat known to the people who are in my Friends circle. Hey, that's the entire point of G+, so I really do encourage you to organize your connections on G+ so you can do the same...

Once I'm done specifying which Circle or Circles I want included, I click on "Enable Chat" and I'm good to go!

Let's tweak things just a bit more, however. Just to the right of the "Available" indicator (and note that I get the green video camera icon indicating I am available for a video chat) there's another tiny grey downward pointing triangle. Click on it and a menu pops up:

Choose "Chat settings" and you'll see...

Interesting options here, but click on the link "Verify your settings" to make sure everything's working properly with Google chat / G+ chat:

Here you can see that my video camera is working fine, though having back lighting makes it easy for me to have a witness-protection-program-style silhouette, not so good for an actually face-to-face conversation! I'm also talking so you can see that the little indicator just above "Mic indicator" isn't empty. That's good.

It all looks good. Now, to initiate a text chat!

To do that, I simply find a friend who is available (denoted by the green circular icon next to their name) and click on their name. The result is a small pop-up window on the lower right of the page. A few back-and-forth messages with my friend Chris and here's what I see:

Notice that I'm typing into the bottom portion, about to send "got that. hope it's all going well, though..."

Simple, straightforward, and you're ready to chat with your friends and colleagues, whether it's about some cool new TV show you're both watching or the latest drama in the office!