In the past, in-browser QuickTime controls were extremely awkward. Loading an MP3 track in Safari, for instance, would yield controls that were incredibly tiny. Things have gotten a little bit better with the latest Safari release.
You can now use the zoom feature, via the View » Zoom In (or Out) menu items (and their keyboard shortcuts), or by using "pinch-to-zoom" if you're on a laptop.
The controls can now be much larger, although the scrobbling icon is at a fairly poor resolution.
[robg adds: As submitted, this hint discussed QuickTime X as the source of zoomable controller, but it seems to be based on Safari's page zoom feature. Although Firefox also has a page zoom feature, it won't zoom the QuickTime controller. This hint should work in both 10.5 and 10.6.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090904141614470