/http:\/\/(.*?\?.*?)[^\'\"><]*/i

http://blabla.com/list">http://babla.com/list</a><br/><br/>blabla <font size=1><a href="mailto:admin ]at[blabla.com?

    $test = array('http://blabla.com/list">http://bla-bla.com/list?a=b</a><br/><br/>admin ]at[blabla.com?ddd',
        'noturl http://blabla.com/list http://bla-bla.com/list?a=b',
        'noturl http://blabla.com/list http://bla-bla.com/list?a=b notend',
        'noturl http://blabla.com/list http://bla-bla.com/list?a=b notend http://another-url2.com/list?query');

    $re = '/http:\/\/([^\'\"><\s]+\?[^\'\"><\s]*)/is';

    foreach($test as $t)
    {
        print "test: '$t'\n";
        preg_match_all($re, $t, $r);
        foreach($r[1] as $match) print "match: $match\n";
    }

# ./test.php
test: 'http://blabla.com/list">http://bla-bla.com/list?a=b</a><br/><br/>admin ]at[blabla.com?ddd'
match: bla-bla.com/list?a=b
test: 'noturl http://blabla.com/list http://bla-bla.com/list?a=b'
match: bla-bla.com/list?a=b
test: 'noturl http://blabla.com/list http://bla-bla.com/list?a=b notend'
match: bla-bla.com/list?a=b
test: 'noturl http://blabla.com/list http://bla-bla.com/list?a=b notend http://another-url2.com/list?query'
match: bla-bla.com/list?a=b
match: another-url2.com/list?query

$re = '/http:\/\/([^\'\"><\s]+\?[^\'\"><\s]*)/is';

<font color="red">http://www.blabla.com/cgi/action.cgi?id=164</font><br>
.....
">http://blabla.com?id=albalb</a><br/>