The Maxmind GeoIP API is now available as a TCL extension
You can download it from http://www.maxmind.com/app/tcl . You need to have the C API built and installed (as well as the necessary database files) before you can use it.
Here's a simple example:
package require geoip geoip open -type isp ;# open the ISP database (error if not installed) puts "country = [geoip country_code_by_name wiki.tcl.tk]" puts "isp = [geoip name_by_name wiki.tcl.tk]"
This generates (as of July 2006):
country = DE isp = IPX Server GmbH