dynamic sql statements and OUT variables

1) How do I get the value back for this dynamic statement?

minUserID := execute ''SELECT MIN(userid) as minID FROM '' ||
campQueueTableName;

campQueueTableName and minUserID are variables. The language is plpgsql. I
want the value of what comes back in the MIN to be stored in the variable.

2) How do I do this?

Select myValue := userid FROM table1;

Where I want the value of what comes out from userid col, to go into the
variable declared as myValue. Language is plpgsql.

Thanks,

Girish