its in the best interest of all the countries that export products to Europe to try and keep it together. Just yesterday Japan annonuced they will buy sovereign bonds to help keep it going. China did this previously.
If the eurozone does collpase it will send a shock wave through the global economy and screw up (credit will freeze upa gain) the financial markets for an extended period. Reminder a lot of banks and others outside of the eurozone hold EU sovereign debt.