Importing Subscribers:
First, obviously, you've got to have the membership created in Nanacast. Second, you'll need  a properly formatted export file from your CRM with subscriber data.
The following knowledgebase article is a basic outline of the import process in general (disregard any specific references to our Memberlock plugin if they don't apply to your scenario):

http://www.nanacast.com/support/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=170

Export/Import file format:
You'll want a header row with all your data columns in it, and one row of data for each subscriber. In addition to any Custom Fields you have set on the Notifications/Custom Fields page of your membership, you can set the column names to match any of the following applicable supported fields:

First Name
Last Name
Email
Next Billing Date (Must be YYYY-MM-DD)
Effective Start Date For Content Delivery (Must be YYYY-MM-DD)
Billing Amount (Ex: 11.95)
Billing Interval in Days (Ex: 30)
Installments Needed (Enter 0 if never-ending)
Recurring Affiliate Commission (Ex: 5.35)
Recurring 2-Tier Affiliate Commission (Ex: 5.35)
Nanacast.com Affiliate ID
2-Tier Nanacast.com Affiliate ID
Credit Card Number
Credit Card Expiration Date (Must be YYYYMM)
Billing First Name
Billing Last Name
Billing Address
Billing City
Billing State/Province
Billing Zip/Postal Code
Billing Country
Billing Phone
Shipping Method at Checkout
Shipping Method for Recurring Shipments

Custom Fields: Add any custom fields on the Notifications/Custom fields page of the membership first before the import, and then your custom field name will be included in the list of supported fields on the "Import Clients Step 2" page of the import process.

Once you've got your membership and your properly formatted file created, you're ready to import.
In the Overview menu for the membership, in the Members area, you'll see an "Import" link, which will take you to the import clients page:


Here, you can import a CSV/XLS formatted file with your subscriber data:


Click “Choose File” button. Browse for your exported subscriber data file in the location you saved it, and select file.


 

Once the file is uploaded, the file name will show. Once the file name is showing, click the “Import Clients” button.

 

 

In the second step, the form data fields already captured for subscribers will show as selected in the “Import To:” column. Match up any applicable data columns from your file with the supported Nanacast.com data fields.

For the “Do Not Import First Row” option if your subscriber export files contains header row information as recommended, checking this option is recommended.

Select any other options desired.

Click the “Finish Import” button


The results of the import will be displayed, along with any errors.

Billing:

If your strategy is to migrate clients to paying via credit card on Nanacast, you'd want to be sure that your export/import file includes the fields 'Next Billing Date', 'Billing Amount', 'Billing Interval in Days' and 'Installments Needed'. This will cause the system to attempt a billing on the designated 'Next Billing Date' for each client.