Homebrew PCBs

Brian Lalor wrote: 
> Does anyone know if it\u2019s possible to tell Eagle that standard holes  
> for through-hole components aren\u2019t automatically attached to both top  
> and bottom layers? 

There is this simple, long used, funny English acronym: RTFM. Was a bit
over used by open source communities, and became unfriendly to newbies.
Maybe STFG/GIYF/JFGI should replace it now. 

> I ended up with an isolated ground plane on my first board.  

http://www.cadsoft.de/faq.htm.en#06013001


If you want to use the autorouter for single layer, some people use
tRestrict layer (41) to avoid top tracks.