Defoss,
I suspect this is not quite the answer you want, but you will not become an expert in Excel data management in a short amount of time. Expertise is rarely the result of study, but rather achieved through a combination of study and application. Data management, in and of itself, is a field requiring a great deal of training and experience. Using Excel for that purpose is probably another whole field.
With those caveats, I would recommend a couple of general Excel books, depending on your existing knowledge, and depending on how you find you learn best. The SAMS Teach Yourself series (eg. Teach Yourself Excel 2007 in 24 hours) are generally good for learners who want to be walked through the various procedures as part of the learning process. If you are more the type of person who prefers to discover things for themself (which is the way I tend to learn best), and just need a good reference, I've alway been fond of the Que Special Editions (eg. Special Edition Using Microsoft Office Excel 2007).
The more familiarity you have with data management and analysis, the better off you are. Excel is simply the tool. In the end, you could do the same work with any spreadsheet (albeit, with more or less work, depending on the program.) I have to admit that I'm not as well read in this area, so I'll leave it to others to suggest a good text on data management.
David B.