As Neil suggests the SQL Database recovery options affect what happens to the transaction log size; however I'd suggest you take your backup/recovery strategy into account before changing this.
Another consideration is that the import process by default modifies a lot of records. Update Rollup 8 introduced an optimised process which I expect would significantly reduce the number of records that are updated, and hence the impact on the transaction
log. This needs to be enabled via the registry, as described in
http://support.microsoft.com/kb/977867
Microsoft CRM MVP -
http://mscrmuk.blogspot.com http://www.excitation.co.uk