First, buy a Mac. Then

Option 1 (uses bash): add the following to your ~/.bash_profile

function rem {
for b in "$@"
do
osascript -e "tell app \"Finder\" to delete POSIX file \"${PWD}/$b\""
done
}

Then type 'source ~/.bash_profile' in Terminal.

Or Option 2 (uses Python and gives slightly more meaningful error messages): make an executable file called 'rem' somewhere in your $PATH:

#! /usr/bin/python
import os
import sys
if len(sys.argv) > 1:
    for arg in sys.argv[1:]:
        if os.path.exists(arg):
            os.system('osascript -e \'tell app "Finder" '
                      + 'to move the POSIX file "'
                      + os.path.abspath(arg) + '" to trash\'')
        else:
            print "Error:", os.path.abspath(arg), "does not exist"
else:
    print "usage: rem file(s)"
    print "       move file(s) to Trash"

Now, either way, to move 'blah.txt' to Trash, simply type 'rem blah.txt'. Wildcards and lists of files are permitted. You even get the sound effects!

(This makes use of Applescript and works for me on OS X Tiger and Leopard. Thanks to kw for pointing out the problem with Option 1 and leading me to think of an alternative - 3 July 2008. And thanks for icke for showing me how to make the bash version work all the time - 6 Nov 2008.)