Clean up, de-dupe and upload large excel contact info into salesforce.com

With strong prior experience of excel and salesforce.com you will knouw how to efficiently structure contact file info and prepare for uploading. Project is to consolidate and de-dupe several large excel files (10,000 to 60,000 contacts totalling over 100k contacts). Thought needs giving to how to create account structures to ensure multiple contacts in same organisation are recorded correctly and not into multiple instances of the same company. Please quote a price for a project of 100,000 excel contacts and a timeframe to deliver with your prior experience of similar salesforce activity. Further admin / database projects to follow.