Hmmm... so which one is the foreign key and which one is the primary key? Or more importantly which table is the foreign key referencing?
I tend to use pk_<tableName> and fk_<thisTableName>_<referrencingTableName>. If you wanted to know the columns being referrenced then the information is within the key.
What would happen with a composite unique key made up of three columns? I'd just do this:
uk_<tablename>