Hey there, love your module, however it needs more testing.
After the better part of a day plugging away at it I still can't get it to display the World Shipping Rates correctly when I "Click to calculate shipping". It would display $0.00 every time, but after I dug into the code for a while I figured out why but I still couldn't get it to display properly. There are some issues going on in the uc_worldquote_quote function.
uc_worldquote.module - Line 474
$units = $product->units;
should read
$units = $product->weight_units;
My goal was to create three regional flat-rate shipping costs: US ($15), Canada($5) and International($20). (If anyone has successfully configured something like this already please, please, please let me know how you did it. 
) I had some issues when the code passes through uc_worldquote.module - function uc_worldquote_quote - Lines 498-504
$rules = uc_worldquote_get_rules();
//remove all the rules that don't apply to the pkgwieght
$rules = uc_worldquote_match_weight($rules, $pkgweight);
//remove all rules that don't apply to the shipping infomration
$rules = uc_worldquote_match_area($rules, $postal_code, $zone, $country);
The rules array is populated correctly, but then the uc_worldquote_match_weight clears all my rules before it gets to the rule filter for the area matching I need. If I comment out the function call to uc_worldquote_match_area, then I get the correct area rules returned. Not too sure how to fix this, but if I get some time I'll look into it later.
One final (super minor note), a little spelling mistake: uc_worldquote.module - Line 363
'title' => t('Wolrd Quote Shipping'),
Once again. This module kicks butt! I can't wait till it's all finished. I'll lend a hand when I have more time. In the mean time, keep up the great work and many thanks.
Robin