I ordered this bag from a national retailer, instead of eBags (as is this Amazon listing).  According to the description, this bag is "nylon or cotton." It looks and feels like natural cotton canvas (fairly obvious just by looking at the bag and it's 'eco-green' tags, and also the stray threads found in the bag).

I love the simplicity of the bag. It can be used for the bare minimum or it can hold everything but the kitchen sink - all neatly organized in the various pockets. I absolutely love the patch of leather at the bottom. This protects the bag as well as gives it that high-end feel. The extendable strap is very sturdy and adjusts nicely, and it will be nice being hands-free and knowing my stuff is secure.

I snagged this bag on sale at a price comparable to what it's currently being sold at here.  In reality the look, feel, and quality almost make this item worth paying full price... ALMOST.  I hope to get lots of use out of it; and I definitely recommend the bag, despite a few design setbacks (thin lining, oddly sized zippers, etc).

**UPDATE 9/4/2011**

I've used this crossbody daily and while I really enjoy it's simplicity, there are a few downsides as well.  The tiny pockets are actually very smart places to keep keys, lipgloss, antibacterial gel, memory stick, earbuds, usb cord, you name it!  And while the inside of the mini bag CAN hold many items, it easily gets weighed down and it becomes difficult to sort through the inside quickly - you have to keep your stuff in an organized and clutter-free way for this bag to be at all useful.  Also not only does the shoulder strap remind me of a camera bag (the additional "shoulder pad" looks a bit silly), but the strap can rub against the skin and cause irritation (probably from either being too heavy or not staying on my shirt).  Again while this is definitely a cute/functional mini bag, just be aware that it isn't without its negative points.