Mine gives just over an hour at best. There's an IBM battery information thing you get by clicking on the battery information icon on the Windows XP toolbar. Left-click once and choose 'battey information' There are various tabs with info - one of which shows the battery health (mine is amber/yellow now - should be green) and another shows the full charge capacity vs. the maximum rated for the battery when new. I think mine is about 18 vs 42 when new. Sorry if the above is a bit inaccurate - am using a cra**y dell at work at the moment!
You can also find the number of times the battery has been recycled (charged). If you do decide to replace the battery with one from Wan Chai - probably worth taking your laptop along, getting them to fit the battery and then checking that the battery has never been recycled (or only a small number of times in the factory). Always a risk you'll get a 2nd hand one (I'm a cynic)
Try here if you don't have the IBM utility installed: http://www-307.ibm.com/pc/support/si...cid=MIGR-44226