We want to be able to assigned someone as an "interested party" to an account, and then notify that interested party when someone else is the cases owner of a case for that account.
Can be any number of emails on the account layout).

The 'interested party'  should be at the account level. . Maybe there could be a box where emails addresses for interested parties could be entered and then a flag to say notify them or not.
 but generally we want to be able to assigned someone as an "interested party" to an account, and then notify that interested party when someone else is the cases owner of a case for that account.

We would only want management to assign someone as a interested party."



Approach: Creat a object called interested party and MD realtion to account. add that to related list of account. Have user enter any # of emails....and create a trigger on case to send email when after insert and after update...

some questions i my mind....how can enter mutiple users ..should i do a look up to users on the intrested party object...even then how can i achive more than one email?

also this is not possible via workflow as i will have list of users...

if trigger is the option...how can i get the email from user and associate that to case?