Some webmasters at DigitalPoint Forums are suggesting that Google Analytics is updating more frequently than every 24 hours.
One member said they update every hour and lag about 3 hours behind in reporting:
mine updates about every hour, and is almost always exactly 3-hours behind.
Others suggest it is more like every few hours.
But if you take a look at the Google Analytics help center, which says:
How often is the data in the reports updated?Report data is generally updated every 24 hours, but data may sometimes take longer to appear in your account. AdWords cost information is imported once daily, to import the previous day's information.
So who to believe?
It seems like I saw an early update this weekend, but I was not a 100% sure. 24 hour updates make most sense to me. Here is a poll where you can add your two cents:
Forum discussion at DigitalPoint Forums.

Comments:
William Vicary
10/22/2007 04:16 pm
You might notice that they display the month, and only display full days, if you click the drop down box (where you can select what days to look at) you can select the current day and it will show traffic for that specific days. I find this lags behind a few hours (around 3 like you quoted) aswell.
Lorenz Lammens
10/23/2007 02:07 pm
Analytics is reporting with only three hours delay. I have been noticing this since the first week of September.
Glenn Abel
11/05/2007 09:40 pm
Seems like every couple of hours, consistently.