Be carefull when choosing your default content access account... for more info take a look at this Knowledge base article -
Search results include draft documents in SharePoint Server 2007
Article ID : 928623
Last Review : February 22, 2007
Revision : 1.1
You upgrade a computer that is running Microsoft Office SharePoint Portal Server 2003 in a farm environment to Microsoft Office SharePoint Server 2007. However, when you perform a search on the SharePoint Server 2007 site, the search results include draft documents.
This issue occurs when the default content access account under Search Settings in SharePoint Server 2007 Shared Services Administration is configured to use the SharePoint Server farm administrator account.
To resolve this issue, change the default content access account to use an account other than the SharePoint Server farm administrator account. To do this, follow these steps:
1. Click Start, point to Administrative Tools, and then click SharePoint 3.0 Central Administration.
2. On the Central Administration page, click Shared Services Administration.
3. On the Manage this Farm's Shared Services page, click the default Shared Services Provider.
4. On the default Shared Services Provider page, click Search Settings.
5. On the Configure Search Settings page, click Default Content Access Account.
6. On the Default Content Access Account page, type an account that you want to use for the default content access account, and then click OK.
7. Repeat steps 1 to 6 on each Shared Services Provider that is created when you upgrade the SharePoint Portal Server 2003 site.