When you have generated your specification, ensure that it is checked by other people in your organisation. You should get them to sign a copy of the specification to say they approve of its contents. They should be allowed to say that they hate your project.... it's much cheaper to listen now than when you've bought the project and they refuse to use it!

Provide the same specification to the companies you would like to quote, bearing in mind the suggestions earlier. Have a reasonable deadline for them to come back to you with prices. Provide a means for them to obtain clarification of key points, but ensure that you don't grant concessions to one bidder without telling the others.

Remember that you might need to include moving data from old systems, generating entirely new data, linking in to other systems, and staff training in your specification.

Ensure that you ask for a reasonable warranty period (eg 3 months or more) during which all bugs will be fixed.