Via VT6656 USB WiFi has been out-of-tree because of non-GPLness. The new driver is a candidate for inclusion supposedly but for now you need to build your own driver in most cases. I want it for Debian 5 on my DT360.
This article details the process of building the stock firmware for the SMCWAPS-G from the sources on Ubuntu Hardy (8.04.1.) The SMC SMCWAPS-G is on one hand an 802.11g access point with two USB2 ports and a 2.5" form factor ATA/IDE connector, and on the other a small and extremely low power consumption x86-compatible linux-based server with the same. While the included GPL compliance CD is relatively worthless to the casual user, the company does make the same content available in a more useful form for free download via their web site. This article explains how I built the sources; Read my review of the SMCWAPS-G for more information on the device in general.
Not so long ago I purchased a Belkin F5D7230-4 access point new in the box at a pawn shop. This seemed like a sweet little unit and just what I was looking for. While I'd like to put a customized release of Linux on an AP this isn't actually necessary to me, it only (potentially) provides additional functionality, so the Belkin unit was a potentially acceptable solution. Unfortunately, it demonstrated an inability to provide long uptimes (read: it locked up a lot) so I had to look for a replacement.
There is a pawn shop in Ukiah near my favorite cheap Sushi restaurant which often has interesting goodies; while most of their floor space is given over to antiques and collectibles they have a couple of racks of tools and usually a small selection of electronics as well. Last time I was in there, I picked up one of these access points new in the box for $30 - not an amazing price (right now you can get one NIB from amazon for $25 shipped) but it satisfied my need for instant gratification. I've been stumbling along with only 802.11b for years now (I got my Linksys WAP11 as part of a trade) and I was long past due for an upgrade.