i have the core installation i.e. the Office and productivty and the Development install for the Fedora Core 6 64 bit version..
Now that i have got the network configured and running. I want to get the fedora extras installed. For that i keep trying to run the software installer in the applicatoins menu and/or the update manager...
Both these applications seem to hang at the stage of "retrieving software information'/'retrieving update information', Is there any setup which i have to do for the correct repositories to be accessed ? even when i insert the FC6 CDs the software manager does not recognise them as repositories.. it does not even reach that stage.
Any reasons why this happens and possible solutions ?

Pirut (=the add/remove software utility) does not accept dvd as a repository by default.

If the updater/installer hangs, it's often because of misconfigured repo files
/etc/yum.repos.d/fedora-core.repo
/etc/yum.repos.d/fedora-extras.repo
/etc/yum.repos.d/fedor-updates.repo
You need to make sure that the first baseurl in all three files is uncommented (no hash in front themj). Some also prefer replacing the default url with a mirror that is closer to them; but it's not something I recommend until you have learned a bit more about fedora.

have already configured the urls in the repos directory in each of the files..
yum runs fine from command line but the pup and the pirut utilities just hang when i try to run them..
now what do i do ?

Well, if this is a fresh install we're talking about, then you're probably just seeing the effects of the automatic updater. Since Fedora wants to protect you from doing double updates, you can have only one updater at a time. In other words, while the automatic updater is running, you cannot use yum or pirut. It is usually quite fast - except after a fresh install, when it has so many files to check and updates to retrieve that it could easily take half an hour or more before it pops up a box to inform you that there are over a hundred updates available (=800+ MB when I installed last month...).

Edit: if yum is doing OK, then clearly all of this isn't much of an explanation. Sorry for overlooking this part. Are you sure that the "enabled" item is set to 1 in your repo files?