Q: While you can directly add email addresses from Gmail, Yahoo or Windows Live Hotmail accounts into LinkedIn using the import contact feature, what are the options for people who using another webmail program like Gmail for Google Apps?
A: The answer is fairly simple. If your email is hosted on a web domain that’s not directly supported by LinkedIn (like @microsoft.com or @googlemail.com), you can still easily import email contacts into LinkedIn using the CSV option.
Just export all entries of your address book into the Outlook CSV format and upload the file here. Then select the contacts you wish to invite on LinkedIn and done.
Related: Compare Gmail with Google Apps Premier
PS: If your email address is Rediff, Indiatimes or Gmx, select the "other" option on the webmail import page and select the appropriate domain from the drop down – no need for you to do the import-export exercise.