[Freegis-list] Suggestions for web mapping system?

[Rory Kingan]

Hi,

I'm new to gis and a little overwhelmed by all the freegis systems,
data, etc available so I'm looking for some pointers for a system I'd
like to build.

What I want to make is a (non-commercial) website to display Wifi
coverage in the UK, in particular London.  Assuming I gather a list of
all these wireless transmitter nodes and information about where they
are and their approximate coverage range I want to draw maps showing
the nodes and their coverage zones, overlaid upon a street map of
london.  People should be able to click on a node to get various
details about it, zoom in and out, pan, etc.  They should also be able
to enter their location and see a map showing the nearby nodes.
People might also want to filter out nodes based on properties like
whether they're free, whether they're in a cafe / bar, etc.

There are some sites out there that pretty much do this, for example
www.totalhotspots.com.  However, they all seem a bit dumb in some way
or another, and/or they're oriented towards pay-for services instead
of free wireless.

So my questions are:
 - Anyone know anything exactly like this?
 - Anyone know of similar applications using freegis that I could look at?
 - What freegis software should I use to do this?
 - What free data is available for street maps in london?  (preferably
whole of the UK)
 - If full streetmap data isn't freely available, how about just some
coarse features like parks, main roads, anything that will be better
than just circles on a blank background?
 - Any recommended reference material for a newbie to GIS that would
be useful for this sort of application?
 - Anything else I should know or questions I should have asked?

thanks in advance,

Rory