There are a couple of bugs in the code that you need to fix in order for it to conform to the the theme and look better overall. Here are the fixes and hopefully the author will include them in the next release:
Within the file ics-import.php do the following:
1. Change line 325 from:
print "<h2>".$widget['widget_title'].'</h2><ul>';
to: print $widget['widget_title'].'<ul>';
2. Add the line: extract($args, EXTR_SKIP);
somewhere after: global $dl_pluginICS;
(probably around line 296)
That should make it work like any other sidebar widget. Hope it helps!
Peace,
Brian