When you select "Contacts" from the left side navigation bar, iBackup Viewer will load the backed up contacts, and it will look like:

Change the group from group drop down to show contacts within the group, you can search to find  contacts match to given keywords.

iBackup Viewer shows contacts in ascending order by default, and sorts by full names.

The sorting result depends on the system locale settings.

To Mac Address Book

Save All to Contacts

You can export all contacts to system address book, actually the ( prior to Lion)

Save All to Groups

This option behaviors almost same as "Save All to Contacts", but it will try to put the contacts in to groups and create the groups if they are not existing.

Save Person

If you would like to save only the chosen contact to system address book, select this option.

Contacts to vCards

If you want to share backed up contacts for some usage, the best way is using vCards, which is known as *.vcf files.

Save Person to vCard

Write the selected contact to vCard file.

Save All as vCards

Write out all contacts as separate .vcf files.