[Have a newer Volvo? See this S80, S60 and V70 2001+ Oil Change DIY forum topic.]
NOTE: Best is to do this with warm engine, so after a trip somewhere, park it at home and let it cool down for 30 minutes or so. I change my oil twice a year, or about 5K-6K miles. I don’t want to get into a debate about change interval (Maintenance minder, 5K, 7.5K, 10K, and so on). This is what I do and is what I believe in: every 5-6K miles or so.
* WINTER: 5W30 Synthetic Oil for easier cold start.
* SUMMER: 10W30 Synthetic Oil (Standard Oil is fine too).