Don't get too worried, interest rates are still incredibly low, and still below 4%.  But after four weeks at record lows, the average 30-year mortgage interest rate increased from 3.87% to 3.95%

"The rise in rates is a vote of confidence for the housing market, which continues to show signs of gradual improvement, said Frank Nothaft, Freddie Mac's chief economist."

Other factors affecting more optimism in the housing market:

• decline in # of borrowers who are seriously delinquent on their loans
• increase in new home construction
• stronger pace of existing home sales
  

More details here at CNN Money.