yes
If you file 485 (application for adjustment of status) before your H-1 expires, you will be considered 'adjsutee' and you will be 'in status' until the decision of your 485 is reached - no matter how long that takes by INS.
If you have not completed six years on H-1, it is a godo idea to file for the extension also (along with 485). 485 has nothing to do with H-1, and the renewal will not affect 485.
If you do not want to extend H-1, note that, 'adjustee' status does not allow you to work UNLESS you have an EAD. So, if you file 485, don't forget to file EAD simulataneously. You SHOULD have EAD in hand on or before Sep 30th 2002. If you do not get it by then, you can not continue working.