Whether you are importing Leads or Contacts/Accounts into SalesLogix you need to make sure that you import clean data.
My personal belief is that you need to clean the data prior to import, not import first and then clean up your data.
One of the first things you need to do with import data is to make sure that you have a unique Identifier column in your spreadsheet. That is a easy as putting in 1,2,3 and then pulling down the handle to continue the sequence for the rest of the spreadsheet.
Secondly, I would make sure that my individuals name has separate columns for First Name and Last Name. If not, split it into two columns – this is very easy to do within Excel.
Then, if you have seperate fields for Area Code and Phone Number, I would combine these fields into one. This will make it much easier to import, although you can add fields together in the import wizard.
Next, I would delete all columns of data that are not needed in the import. You can copy your spreadsheet and then delete the columns that you do not need for the import, allowing you to preserve the original data in the first spreadsheet.
Although you cannot import to seperate Account Managers via the Wizard, you can import the account manager into a user defined field. This will make it very easy to use the Territory Realignment Wizard to get the proper Account Manager on the records.
Lastly, I would put a unique source on each of your imports. If there is any kind of error and you would like to remove those records, this can easily be done if you have a unique source that you can build a group from and purge the records.