Update - thanks to a commenter who noted that for NOAA also, 2005 was the hottest year. The plot is amended, with 1998 lightly dotted for GISS and NOAA.
The hottest year is shown as a dashed line. If 2010 is ahead by the end, it will be the new hottest year. Most indices lag 1998 now, but 1998 cooled at the end. GISS is ahead of its target, but 2005 didn't cool. Each index is offset by 1.5°C from the next, for visibility.
I'll update this plot regularly at the ongoing temperature site.
Update - Lucia also has a new post on record prospects.