I have filed (e-file through a tax service provider) tax returns for year 2008, my address on the Fed return is incorrect (i.e Street name missing, city and state names are correct); on the State tax return the address is correct no problems.

Am wondering how to correct the address in Fed tax return? Or can I just leave as it is, advice

Complete a Form 8822, Address Change Request, to change your address with the IRS.

You can also wait until the 2009 tax return and file with the correct address then. This is a very viable option if you are going to move in the next 6 - 8 months.