I keep hearing that mortgage rates will probably hold steady until mid-2008. They've already increased from 6.15 to 6.75 in the past 6 weeks. I'm building a house, and won't be able to lock in a mortgage rate until probably mid-August. Should I "buy" my mortgage rate at 6.75% now for $750, or should I hold off? What are the odds that rates will top 7.25% within the next three months?