Topozone.com used to dynamically display lat/long coordinates on their maps which you could access for free.  Came in very handy for placing buildings exactly where they're supposed to be when adding new scenery.

They're a pay site now so although you can still view the topomaps, they don't display the lat/long unless you have an account with them and are logged in (I'm very curious as to how much traffic their site gets now...). 

Does anyone know of any free topo sites on the web where this information is still available?

Continental US.

Thanks ziliu.  Another site is http://www.terraserver.com .

For those sites that show coordinates in decimal form (not sure if those are usuable in the scenery XML fie?) you can convert them to deg/min/sec at this site:  http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html

Haven't tried it yet but it looks fairly self-explanatory.