$ port selfupdateThe issue is simply that you have all your libs and binaries managed via MacPorts compiled for the i386 architecture and not x86-64 (as required for Snow Leopard).
dlopen(/Library/Tcl/macports1.0/MacPorts.dylib, 10): no suitable image
found. Did find:
/Library/Tcl/macports1.0/MacPorts.dylib: mach-o, but wrong architecture
("package ifneeded macports 1.0" script)
invoked from within
"package require macports"
(file "/opt/local/bin/port" line 39)
The solution is simple, but, arduous. You need to install the new version of MacPorts for Snow Leopard, make a backup list of the installed ports, delete them and reinstall the ones you still want.
You may want to pay close attention to the variants of the ports that you had previously installed when reinstalling them.
Also, you need the latest version of Xcode (a version greater than v3.0 will do) installed.
See the following two URLs for more info: