Anjaneya, it is not clear what exactly you would like to do with your iPhone contacts. You can use the iCloud to bring all your contacts in one place and then edit them if you wish by logging in to the iCloud from your PC.
Other than the iCloud, there exist numerous ways in which you can
manage iPhone contacts and bring them all in one place: ranging from third-party contact iPhone apps which sync your contacts from multiple accounts into your iPhone to apps designed for the PC to import-export iPhone contacts.
Finally, the old and certain way is through syncing your iPhone contacts to your Windows Contacts via iTunes. Then simply edit the *.csv entries found within your Windows Contacts (or Address Book if you are on Windows XP).