Trick 1: You cannot find direct links to Linkedin Jobs page but if you visit http://www.linkedin.com/jobs You can search jobs even you are not authenticated with your Linkedin account.
If you search a keyword in the unauthenticated Linkedin Jobs page http://www.linkedin.com/jobs
The location will be default USA.
The last but the trick i love most is
If you make a search for a keyword when you logged in to your linkedin account.
It will first search the jobs listed in your country if there is no result for the keyword, then you will see a link to search the keyword in the worldwide.
Again there is no direct checkbox or setting for this. But if you use the following URL
you can search your keyword worldwide.
for example if you want to search the jobs includes keyword "linux" in worlwide you can use the following url