SevenCubed - 3:04 am on Mar 7, 2011 (gmt 0)
I know this has been mentioned elsewhere in the forum for other slow loading external resources but it's worth repeating here.
Assign a defined amount of browser real-estate to the AdSense blocks such as:
<div id="adsense" style="height:100px; width:800px;">
...AdSense code in here...
That will allow the browser to continue to render the rest of the page while waiting for google to respond.
Without a predefined block the browser has to wait for that response to complete before it can continue. It might save a bit of time. But other than that it's up to google to "do as they say".