Tcl Style Guide and Engineering Manual site

ftp://ftp.tcl.tk/pub/tcl/doc/

Some Tcl Debugging tricks and tips

http://en.wikibooks.org/wiki/Tcl_Programming/Debugging

Tcl for Web Nerds

A book by Philip Greenspun, Hal Abelson, Lydia Sandon
http://philip.greenspun.com/tcl/index.adp

AOL Server referenced here