To reproduce in Moodle 2.1.2+ (Build: 20111118):

• create a URL resource pointing to something such as http://anotherdomain.tld/myscript.php?id=31
• on the parameter section, add a parameter such as "info" and select as variable to send "Username"
• save and return to course
• the URL for the resource is http://anotherdomain.tld/myscript.php?id=31?info=username, while it should be http://anotherdomain.tld/myscript.php?id=31&info=username

It appears a regression, adding a URL resource in the very same way as above in Moodle 2.1.2 (Build: 20111010) the URL syntax is correct: http://anotherdomain.tld/myscript.php?id=31&info=username