From your description, it looks like you have a customer portal page to capture their details and you want this data to be stored in MS CRM for doing campaigning.
Well, if you already have accumulated the data in your database then it needs to be migrated. Migration can be done in bulk using data import feature of MS CRM by exporting data from your database in csv/xml format and then importing in MS CRM.
Going forward if you want to store the customer/prospect details directly into MS CRM, you can integrate your customer portal page directly to MS CRM using web services. See the customer portal available at microsoft pinpoint or the SDK. You'll need some
technical expertise for all these things.
- Arvind