Freestockcharts.comFreeStockCharts.com keeps some intra-day trading history. You have to create an account to look up individual stocks. Once you create a free account you can get intra-day trading history for the last month (Hourly for past month, 15 minutes for past week, 1 minute for past day). Going back past one month and it only keeps daily close history.
Here is Family Dollary's (FDO) hourly intra-day chart for the past month: