kat--Hubby does a lot of indexing, inventorying, and keeping of records in MS Excel, but again, this may be overkill for what you want to do.
For my book, collectibles, and garden inventories, I use a simple little database program called (appropriately enough) My Database For Windows. The same company has a mail program for doing mailing lists, and an invoicing program for invoices and estimates. These programs are all cheap (I think they're all around $30 or so) and reasonably easy to learn and use. They're really basic as each program does ONLY the one thing--no bells and whistles. I use both My Database and My Invoices, and like them a lot.
Lin