Fix cracked glass on Samsung Galaxy S

I bought a Samsung Galaxy S from Kijiji and just realized that the glass is cracked.  I didn't see this when I bought it because it was sunny out and the screen was covered in fingerprints.

The touchscreen works fine, and I don't think the oled itself is damaged because when it's on I can't even see the crack unless I look at the phone from an angle.  The crack also extends beyond the screen to the buttons.

I see replacement glass for this phone in ebay for like $15 from hong kong.  Anyone have experience replacing the glass on a Galaxy S?  How difficult is this to do?