pgtclng , aka A PostgreSQL Interface for Tcl, is a fork of pgtcl
With release 1.4, Tcl 7 is no longer supported.
version 2.0 targets PostgreSQL-9.1.0.
Complete Tcl binding to PostgreSQL's libpq library. Version 1.5 (stable) includes support for asynchronous operation, prepared statements, unquoted $1-style variable substitution, looping over select results without managing a result handle (pg_execute), and numerous other enhancements and bug fixes. (See the ChangeLog for more details) CVS tree available at pgfoundry pages above. Current CVS is TEA 3.1 compliant plus connection handles and result handles are commands that work as objects in their own right.
The Postgres src distribution includes the libpgtcl binding (in the src/interfaces directory).
However this is not the latest version.