I use a linksys WRT54G on my home network. It was running the standard Linksys firmware at one point, but I've been running a variety of Linux variants on it over the last few months.
This evening, while looking for information on OpenWRT I stumbled across HotSpotSystem.com.
While several of the alternative firmwares offer hotspot functionality this is the first one I've come across that offers a builtin revenue stream.
I'm not sure how the revenue share works with the commercial offerings from Bitbuzz, Eircom, BT etc., but this alternative does look very appealing.
Pity I don't live somewhere where I could actually make use of it