In terms of 2.4Ghz and 5Ghz atleast in most of the world both are unlicensed radio frequencies, and there are alot of differences in regards to them, aside from the 802.11n protocol.

In terms of the united states the 2.4Ghz band has roughly 14 channels, of which the U.S. allows you to use Channels 1 thru 11. each channel is 22Mhz wide and all frequencies are based on center frequency; the downside to this is that of those 11 channels only 3 are non-overlapping - 1,6,11 so you really only have 3 channels with which to configure devices; although some schools of thought will tell you that you can use 4 channels - 1,4,8,11. Globally it's accepted that you use only the 3 channels - 1,6,11. To use one of the other channels can cause impact to the others around it.

Now in terms of the united states the 5Ghz you have roughly 12 channels 36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157, 161 (although a recent revision has added 100, 104, 108, 112, 116, 136, 140, 165 - not all client adapters support these channels). Unlike 2.4Ghz all of the 5Ghz channels are non-overlapping, so you can actually utilize all the channels.

aside from just the channel issue there is another major difference between them, the 2.4Ghz band is heavily saturated around the world by non-wifi devices such as microwaves, cordless telephones, audio/video senders, security cameras, toys, bluetooth, specialized medical devices, etc. So when implementing a wireless network in the 2.4Ghz range there are a great number of interferring devices to contend with, the 5Ghz frquency is pretty much empty.

Here is a link that covers more about this stuff.

http://en.wikipedia.org/wiki/List_of_WLAN_channels#5.C2.A0GHz_.28802.11a.2Fh.2Fj.2Fn.29

Hope this helps.http://en.wikipedia.org/wiki/List_of_WLAN_channels#5.C2.A0GHz_.28802.11a.2Fh.2Fj.2Fn.29