Yaroslav has a great intro webcast to SharePoint branding and also demonstrates the FireBug add-in to FireFox.
A great list of development tools for SharePoint, found on CodeProject.
This is a great doc from the Office site which you can use to help plan your SharePoint / MOSS service and content access accounts.
Found here on MSDN.
Multiple Authentication Providers (http://www.sharepointblogs.com/andynoon/archive/2007/07/04/defining-multiple-authentication-providers-to-a-single-moss-2007-web-application.aspx) Forms Authentication in MOSS (http://www.codeproject.com/KB/sharepoint/moss_enableforms.aspx) Web Applications, Site Collections, Sites and Sub-Sites (http://www.leonmeijer.nl/archive/2008/03/12/85.aspx) STSADM (http://mystepstones.wordpress.com/2008/02/20/stsadm-extensions-lots-of-useful-new-operations/) STSADM Backup / Restore (http://farhanfaiz.wordpress.com/2008/02/07/mossback-up-and-restore-site-collection-sites-using-stsadm-utility-export-import/)