For a Network Manager, you need to decide what type of network you want to work with (Microsoft, Unix/Linux,...) and then get the appropriate certifications in those systems. Then you need to consider how the network will communicate and be setup (e.g., Cisco). Starting with the basics can't hurt and that might include CompTIA A+ (for Hardware and general OS issues) and Network+ (the basics - but a good place to start). See here for more on these - I posted the A+ page but the others are listed: CompTIA A+. Others like Security and Server are good, but I wouldn't waste my time on them as they are better proven other ways and are not considered by many to prove expertise in either area (and don't really help in terms of learning and proving knowledge of the basics like the other two suggested above).

Assumining Microsoft and Cisco (what I'm familiar with), you probably want to go for the Microsoft MCSE (which is a series of MCP certifications - some required and some optional) MCSE Certification | MCSE Training | Microsoft Certified Systems Engineer and for Cisco you need to work up a chain of various certifications until you get the gold standards - the CCIE and/or CCDE (with which you can pretty much write your own ticket but it is very hard to get and while the earlier certifications are reasonable, the CCIE is VERY expensive - thousands of dollars for the test and many need to take it more than once - I'm not sure about the other). Here's more on Cisco certifications: Certifications Overview - IT Certification and Career Paths - Cisco Systems. Also helpful would be certifications in commonly-used network systems like Microsoft Exchange Server or Microsoft SQL Server = but only after you have the others covered as they are more accepted and acknowledged.

All that said (and with the exception of the CCIE or CCDE which really do prove something), certifications mostly establish book knowledge - which is good and many companies expect their people to have some certifications or require they be obtained within a few months of being hired as part of the employment contract, I required my field technicians to get an MCSE within 4 months of being hired if they didn't already have it (and I did show preference for hiring people with it all other things equal). But MUCH more valuable is actual experience as an Administrator or an Engineer either working for a single company or, preferably at least to me, at a company that provided such services to other companies and so the technicians got a much broader base of experience in a variety of environments and system configurations. I frankly didn't hire anyone with less than 3 years of experience doing the type of work I'd be expecting them to do for our clients no matter what degrees or certifications they possessed.

And don't expect to become a Manager for quite a few years. You need experience doing the work you will be managing before you can properly manage it. And you will probably need to pace things - first an administrator, then an engineer, then a team leader, then maybe a supervisor and so on before you get anywhere near becoming a manager. If you're good at it and work hard and show both aptitude for the knowledge side as well as the management side (which is a whole other thing that I'm not covering here), it will eventually come to you - but you need to be patient. Seeking the qualifications of an IT Network Manager is a bit premature - you should be looking for the qualifications of becoming a Systems Administrator or a Systems Engineer at this point and then work your way up. That experience will teach you what an IT Network Manager needs to get and do the job.

I hope this helps and wish you all the best.

Good luck!

Lorien has given you the best answer, and far better than I could ever do. I read this a few months ago. Not sure I really agree with it, but I shall post the link anyway: What are the relevant IT certifications in 2010? « Geeks to Go! – Tech experts answer your questions

Oh, and since we had this off topic discussion, about being allowed to go off topic on either post two, or page two, I have decided to go off topic in reply three! Upgrading from Windows 7 32bit to 64bit.