Do command-a to select all addresses. Export the address entries as a VCF file by using the option under File/Export/Export VCard. Then run the VCF file through this convertor to make it a CSV (comma separated value) file. Then import the CSV file into Excel.
Download and install Mozilla Thunderbird. When installed it automatically detects your address book contacts and even preserves the groups. Click on the group you want to export, choose Tools/Export. Choose CSV and save. The CSV file will open in excel.
I've just downloaded the Mozilla application and it has opened and downloaded my contacts but the groups are not present. The groups are the bit I need to allow me to filter and export to excel.