Hi music man:
Check proper belt tension.
Check condition of alternator bearings; if these are worn-out they produce this squeaking sound when electrical load on alternator increases like recharging battery after start or when headlamps are turned on. As battery becomes recharged, the electrical load on the alternator decreases (making it lighter to turn) and that annoying sound ceases.
Hope this will help solve your problem...
cold_farmer
October 2007