Altec Lansing has a well deserved reputation for marketing mid-range audio equipment that produces good sound. They've been one of the biggest players in the PC Audio market for at least the past 10 years, and so it's no real surprise that their new AHS302i headset sounds pretty good for all the PC applications one normally associates with a headset. For example, replacing antiquated textual conversations such as "OMG HAX, WTF!" in Counterstrike with the ability to shout "HAX! HAX!" in Counterstrike Source, and be heard.
For ease of use, the headphones include a rather novel USB dongle that has headphone and microphone jacks, and plugs in to the USB port on your PC. It appears to work by mapping into the Windows sound system, so I wouldn't expect this to work under Linux (at least, without extensive Windows emulation), but in that case you can detach the dongle and use the regular plugs that connect in to it. I'm not altogether sure why it's desirable to map the sound through the USB port in an era when most new computers have front side audio jacks, but it is, as I mentioned, a rather novel device. It's the kind of thing that you'll greatly appreciate if you're one of the few folks with a PC that does not have readily accessible headphones/mic jacks. The USB dongle also features a mute button, but it seems to me that this would really only be useful if it can be connected to a front side USB port.
If you wanted to buy a separate device to do this job (for whatever reason), you'd probably end up spending more than the AHS302i headset costs, since the headphones can easily be found numerous places online for under twenty dollars, and prices as low as 12.99 are listed some places.
The microphone is by no means spectacular, but it produces recognizable recordings of the human voice, which makes it more than sufficient for gaming. The arm that holds the microphone is made of flexible plastic that bends easily but holds its shape pretty well, even if you drop the headphones.
For giggles, I connected the headphones to a turntable and listened to an album that features a dynamic range of instrumentation and pitches that was appropriate to the task (Amon Tobin's excellent Splinter Cell: Chaos Theory soundtrack). The sound quality was better than expected, but the bass reproduction was a little lackluster and I could not get the volume in the headphones very loud even when connected to an amplified source.
For the most part, I found the AHS302i's to be an inexpensive and quite functional solution for a PC headset, but my one real complaint lies with the ergonomic design. The speakers are connected to ear-cups that aren't big enough to actually cup the ear (but are much larger than normal headphones). This isn't a problem by itself, but the cups are pressed against the head by a flexible plastic band, and I found the angle rather uncomfortable. After three or four minutes, I develop a discomfort along the top of my ear from using these headphones. While it's possible to ignore, or adapt to, this discomfort, I found it distracting.
The bottom line is that if you're looking to get a headset for under $20, you'll be hard pressed to find one that sounds better than the AHS302i. That being said, if you can afford to spend more than $20, you might want to look into a more comfortable pair of headphones.