You can buy WiFi Hotspot service from Sprint. I think it's like $30/month.
There used to be a loophole in the stock Optimus S software that allowed people to get free WiFi Hotspot functionality using apps like QuickSettings, but Sprint closed that loophole starting with software version 2.2.1(ZVD
If you root and install a custom ROM, you'll get free Hotspot capability. Instructions for doing so follow.
Maximus consolidated a lot of great information in this post
, but it's perhaps overwhelming for beginners (like me). So after reading a bunch of the stuff above, I'd suggest that people really only need to read the following 2-3 guides in order to understand the terminology & process or rooting and installing a custom ROM.
1) Dishe's Idiots' Guide to Rooting and Custom Roms, Optimus S Edition
, explains the rooting and flashing process and terminology in plain English. As soon as I read that, I understood the process and felt confident enough to try rooting and flashing.
2) Contrary to its title, DrewWalton's Guide to rooting the Optimus S with software version LS670ZVD
, provides detailed, step-by-step instructions for rooting, based on whether you currently have the LS670ZV9
, or LS670ZVC
are) SW version on your Optimus S phone. But Drew Walton now has a much simpler "one-click" utility, called Gingersnap, for rooting, which he describes here
, so you'll probably want to skip reading his other guide. Note that if you follow his Gingersnap guide, after the "Pre-use requirements, download the Gingernsap folder from the link he provides. Unzip it anywhere on your PC. Connect a freshly booted phone via USB. And then double-click the Gingersnap.exe icon in the unzipped Gingersnap folder. It will root your phone. But you'll still have to load a custom recovery (like Xonia) and a custom ROM, so...
3) Lastly check out KSmithInNY's excellent guide
containing the latest ROMs, custom recoveries, etc. I'd probably go with the Reborn ROM.
Note that the links above are to AndroidCentral.com, so you'll need to sign up for a free account there (if you don't already have one) in order to access their links.
Also note that the authors of those guides have posted (in the signatures sections of their posts) links to the procedure for returning your phone to its original, stock condition.
Following the aforementioned guides above should take away the scariness of rooting, get you Hotspot capability, improve performance, and get you some other nice features contained in the these ROMs. I hope this helps.
But in the efforts of full disclosure, I haven't rooted yet because I never accepted the ZVD firmware update, and so I still have Hotspot capability. I'll probably hold off on rooting and installing a custom ROM until Sprint releases an official version of Android 2.3 and the developers in the aforementioned guides can create a custom ROM based on Sprint's version of Android 2.3. But if I didn't have Hotspot functionality, I'd root and install the Reborn ROM right away. Good luck!