Identify Your Data Sources
Start by listing the various data sources that you’re thinking about migrating into Salesforce. For example you might have information in a legacy CRM application, homegrown databases, excel spreadsheets, or in individual contact managers. It’s important to spell out exactly what you hope to migrate, what format it’s in, and how clean it is.

Data Migration Strategies
Once you understand the data you’re working with you’ll want to think carefully about the migration strategy you want to take. Using Salesforce.com for the first time is like moving into a new home. You could bring everything in your old home or you could start fresh, leaving your old information behind. You could also take a hybrid approach where you look through your belongings and determine what to keep and what to leave behind.

Each approach has its merits and will depend on your particular situation. The key is to  keep your new home as clean as possible and only move what is absolutely necessary. Discuss with your team, how valuable is that information? Will your end users really benefit from the data or would it clutter the new system? Would it be alright to archive it elsewhere?

Exporting Data from Your Legacy System
Many customers need help getting data out of their legacy system, the strategy for which is going to vary depending on the application. Most of the time you will be able to export your contacts and accounts to an excel worksheet which can be scrubbed and imported into Salesforce. Note that you'll want to save your excel worksheet as a CSV file, also know as comma seperated value or comma delimited. This makes it easy to import into salesforce using the standard import wizard.

There are other situations where you have to purchase a third party tool such as Goldbox for Goldmine to unlock the relational information. As an alternative we recommend looking into two AppExchange Partners who significantly decrease the time and effort it takes to migrate your data. There's ActNow for Act! users and OKERE which works with both Act! and Goldmine data. These services start at about $195. For more advanced data migration projects such as SalesLogix or proprietary applications it’s probably a good idea to talk to your Account Executive and see if it makes sense to engage a data migration specialist.

Scrubbing Your Data
Once you have your data in an excel spreadsheet, it’s a good idea to scrub it before importing it into saleforce.com. First, going through and weed out dirty data, de-dupe people who may be in the system multiple times, and work on consistent naming conventions. If you find yourself really struggling with de-duplicating and cleansing your data there are a number of great partners on the AppExchange who focus exclusively on data quality.

Another trick to make the import process run smoother is to label the columns in your spreadsheet so that they match up to the corresponding fields in Salesforce (example). If there is a column heading in your spreadsheet which isn't represented by a field in Salesforce, create a custom field. 

Choose an Import Tool
Salesforce.com offers a number of tools to help you import your data. With the Import Wizard is the most common tool by which customers add their data. You can easily map information from an excel worksheet (CSV File) into leads, contacts, accounts, solutions, and custom objects. If you have information that’s relational in nature, such as activities or opportunities, mapping data is a little bit more complex. You’ll need to use the AppExchange Data Loader (Enterprise Edition) or a popular open source tool called the Excel Connector (Professional or Enterprise Edition).

Import Your Data
Now that your data files are in pristine condition and you’ve chosen your import tool, you’ll want to begin the process of loading data into salesforce.com. Make sure you start with a small sample set to test. You don’t want to import a large amount of data until you’re sure what it will look like. If you get stuck at any point, turn to the online community or engage the Salesforce.com Professional Services Team.

AppExchange Data Migration Services

• ActNow: Act!
• IntegrationServices.com: Act! and Goldmine
• View the complete list of Integration Tools on the AppExchange