of course there is difference...toobar PR is just one ip where you can check google PR. usually they are the same out of all DC....but when there is update of PR, they are sometimes different from other datacenter http://www.seocentro.com/tools/search-engines/pagerank-dc.html
What's known as Toolbar PageRank is the crude snapshot of PageRank that the toolbar or other 3rd party tools shows and that gets updated every few months- it's all that publicly anyone knows. However, behind the scenes, Google is using a more complex version of PageRank in the algorithm, which is ahead of the updates that gets so many on dp in such a pointless frenzy.
Generally they are just the same because Google tool bar just get it's result from Google database, sometimes it has difference if the tool bar is getting results from difference Data Centers which are usually not synchronized with their indexed contents..
PR is only a numeric value that shows the importance of a page on the web as seen by Google while the google tool bar that show the Page Rank get their data from Google as well. However, they are not always completely accurate since they are not updated as constantly.They have totally a big difference between the page rank and tool bar page rank, however, if you are asking for the importance which whose weigh in too much i guess their both the same and equal.
Google toolbar PR shows only an approximate PR scale ranging from PR0 to PR 1. Original PR is much higher and accurate than Google toolbar PR. In Google Toolbar , new sites may have PR0 . But originally every new sites starts with an PR of approx 0.15.
Google PR is different server by server (not big different for most of site) Google Toolbar PR is get from http://toolbarqueries.google.com/ and you also can get from another google server
I remembered once the google toolbar could show the PR of a specific page, but now just domain PR. So PR and Google toolbar PR are not the same thing.
Not so much difference. When google update the PR our toolbars also update the PR showing quite accurate results.