You can view the time and allocation profiling graph of your program graphically, using ghcprof. This is a new tool with GHC 4.08, and will eventually be the de-facto standard way of viewing GHC profiles
To run ghcprof, you need daVinci installed, which can be obtained from The Graph Visualisation Tool daVinci. Install one of the binary distributions, and set your DAVINCIHOME environment variable to point to the installation directory.
ghcprof uses an XML-based profiling log format, and you therefore need to run your program with a different option: -px. The file generated is still called <prog>.prof. To see the profile, run ghcprof like this:
$ ghcprof <prog>.prof
which should pop up a window showing the call-graph of your program in glorious detail. More information on using ghcprof can be found at The Cost-Centre Stack Profiling Tool for GHC.
Actually this isn't true any more, we are working on a new tool for displaying heap profiles using Gtk+HS, so ghcprof may go away at some point in the future.
daVinci is sadly not open-source :-(.