Team Foundation Service might be a name that's new to you, especially if you are an iOS developer dabbling in Windows. (If you work at Microsoft, well, your entire life can revolve around the similarly named Team Foundation Server. What's for lunch today? There's probably a query to tell you if you're eating in the cafeteria or sneaking out to Red Robin). Well, the good news is that if you don't already know something beginning with T and F, you don't need to care about it anymore. Feel the stress melt away. For now, with the launch of the new Visual Studio 2013, Team Foundation Service is now to be known as the much more memorable Visual Studio Online.
And yet still you might be thinking "meh". Which is a shame, because Visual Studio Online can do some pretty cool things for you, even if you are still using Xcode to write iOS apps (like some kind of crazy fool - just kidding, I'm still doing that. It's a hard habit to break). For one thing, you can use a basic (and free!) Visual Studio Online account to host your source code.
Not enough for you? Well, if you are an Agile programmer, you've probably got some tools you use to manage sprints, task backlogs, burn outs, monkey-puzzles, soup trains, trouser-wranglers and so on (I might have made up some of those terms). Are you completely happy with those tools? Do they work well when you work other developers? If the answer to either question is "No" or "Stop bugging me", you might want to give Visual Studio Online's tools a try. Even if you aren't keeping your source code there, even if you aren't writing Windows apps, and even if you don't have a PC, you'll find that with a web browser you (and your collaborators) can keep track of your project with professional-level tools. For free.
If you are building Windows apps, you can do some quite impressive stuff with Visual Studio Online. Want to automate builds? And have Microsoft's servers do the actual building for you? Not a problem. You can set up Visual Studio to perform builds for you and your team when you check in an update, or at any scheduled time. Great stuff for smaller dev shops (or bigger ones who don't want to run their own server and employ someone to look after it).
And of course, don't forget to look out for Visual Studio 2013!
The Express versions of Visual Studio 2013 are still free, and you get lots of nice new features. My favorite is a new view of your code that replaces the scroll bar: a sort of miniature map of your source code. Makes it easier to navigate right to the section you need. Cool stuff.