I added a block explorer command in the excellent YubNub (
http://www.yubnub.org).
Basically it just redirects to blockexplorer.com (don't hesitate to donate to this site !)
just type, for instance :
bbe 1Cvvr8AsCfbbVQ2xoWiFD1Gb2VRbGsEf28
in the main search field.
bbe stands for "Bitcoin Block Explorer"