Error handling inside procedure

Hi folks,

I have a piece of code that is performing a value lookup for a single string in my procedure, and it's working great;

select fieldValue INTO tempVariable from myTable;

Then I use the results of tempVariable further down in my procedure.  The problem is that occasionally no value is found and then the entire procedure stops executing.  How can I add an error handler for this?  It's not like I can evaluate the value returned in tempVariable after this line executes because the line fails to complete.  I'm not finding anything in SQL guide but I'm in a rush so maybe i'm not looking in right place.

Thanks,

-Patrick