construct neighbor list from polygon list with user defined distance thresholds, as found in GeoDa?

Hi,

After reading a ESRI shape file I want to create a neighbor list (class nb)
from the polygon list by defining a distance thresholds for example 2500m.
This is a option in GeoDa weights creation. However I couldn't find any
function in R to do this. The function poly2nb is based on the 'Queen'
contiguity method.

Looking at the HTML help for the package ought to get you there, 
alternatively scrolling through help(package=spdep)

RSiteSearch("distance neighbours, restrict=c("functions", "docs")")

gets you there first hit (please recall that the spdep author tries to use 
conservative British English - hence neighbour, randomisation, etc.). 
Other spellings can be abbreviated:

RSiteSearch("distance neigh*", restrict=c("functions"))

gets 7th hit to:

?dnearneigh, that is.

If you need alternatives that are not in spdep (such as mean spanning 
tree), look at packages like ade4 (see the search results for ideas).

Roger

Thanks for your help.
Debs.

Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no