I've gotten this working with the 2.6.3 kernel using NdisWrapper (http://ndiswrapper.sf.net). It's proved to be reliable even for extended use. I have a write-up at rayli.net (http://rayli.net).

This card works very well.
I have tried both ndiswrapper and the rtl8180 driver.
all the step, write-up, logs, infos is at http://404.bizhat.com under Gigafast WF721-AEX or RTL8180 section

I used ndiswrapper to get it going, but I did not have success with the ndiswrapper in the debian repositories. I did this a few months back and now the reason why that was eludes me. I then had to compile the drivers myself and I had a lot of difficulty because MEPIS does not come with the kernel source. I had to set it up and do all the steps directly up to actually compiling it in order to get it to where ndiswrapper could finally build. (This was difficult because I did not know how to get it the source in the state it needed to be - I found out how here (http://www.mepislovers.org/modules/newbb/viewtopic.php?topic_id=1043&viewmode=flat&order=ASC&start=20) - the post by Tremens.)
Once that was settled, the rest of the set up was straightforward (in following the ndiswrapper documentation).

It works extremely well (more reliable than a DWL-122 I have on another Linux system).

This card works very well if you use ndiswrapper. Get the WinXP drivers from the Realtek site (http://www.realtek.com.tw/downloads/...x?Keyword=8180) and use ndiswrapper to install them and you should be good to go.