If it is only for one course, then just place on section zero (= always visible) a resource, choose weblink in popup window, give it a new reference name and fill in the weblink on the second sheet.
(uncheck all the show bar options: your students will not wander to other sites so easy..)
If it are links for all courses AND you have access to the php-code, you could go to ../moodle/course/format/weeks/ and edit format.php
Find a place in the left column and type:
print_side_block_start( "SEARCH ENGINES ", 210,"");
?>
<div align="left"><a href="type here your weblink"
xxx"window.open('type here your weblink','','width=800,height=600');
return false;"><img src="type here the weblocation of an image" width=30 border=0> HSL</a>
</div>
<?php
print_side_block_end();
print_spacer(1, 120, true);
Make as many div sections as you wish. And do the same for other formats.
I did the same on the front-page in index.php (see image)
A longer version is:
<div align="left"><img src="here your image location" width=30>
<A HREF="http://rubistar.4teachers.org/index.php"
TARGET="rubistar.4teachers.org/index.php"
xxx"window.open('http://rubistar.4teachers.org/index.php','','width=720,height=540');
return false;">Rubistart</A></div>