NOTE :- The info below was compiled a year or two ago and I have not verified the current situation but I'll leave it as is until I find otherwise.
The latest Freecom/Yacumo usb stick has a Realtek 2831U chipset and any of the following usb id's: 14aa:0160, 0bda:2831, 2304:022b, 185b:0100, 13d3:3216, 13d3:3220, 13d3:3236, 13d3:3244, 08dd:2103. Latest Windows drivers dates january 2007 and can be downloaded at freecom.com If anyone has any info on how to get these to work or if a specific firmware works, please add it here.
Chipset info at http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=35&Level=4&Conn=3&ProdID=147
UPDATE: Realtek submitted a v0.0.2 of their driver feb 20th 2008. This has been confirmed to function for this Freecom (or Conceptronic) stick with usb id: 14aa:0160 on a 2.6.22.17 kernel. This stick has a MT2061F tuner chip, but this driver also supports the MLX5005 tuner chip. No additional firmware file is needed.
The driver source can be downloaded from [91], but be aware it has only be confirmed to work on devices with usb id 14aa:0160.
For easier installation you can use [92]. Just unpack and do a make and sudo make install.