My employer wants me to get a CCNA certification in the near future. I know the networking basics pretty well, but I don't have any experience with Cisco gear. We're willing to pay for one of the bootcamp-style courses, but I'd like to be able to do some reading about it beforehand.
So, let me know what works/worked for you.
Community wiki, because there's no "right" answer here. However, I feel like it would be a valuable thing to have around, given how many sysadmins end up working with the networking gear.
It depends on what you want to get out of the certification; if it's just to meet your employer's requirement, then I would suggest one of the many self study books out there (I used the official CCNA Certfication Library and this study guide from Sybex.) A few weeks of self-study, and you should be able to pass the exam without much trouble.
On the other hand, if you are looking for more than simply passing the test, I would suggest getting one of the above books and working through applying the concepts you learn using lab scenarios. GNS3 is an excellent graphical front end to the DynaMIPS router emulator. You will have to provide your own IOS images; if your company has a valid service contract, you can download these from Cisco's website.
I learnt from the official CCNA Certification Library which really helped me - essential reading for revision as well, I found. Many of the examples in there will seem familiar when it comes to doing your written tests (though not on the final, admittedly).
A "boot-camp" course will not teach you enough, you'll very quickly lag behind on some of the more obscure parts such as Frame Relay etc., and you'll never remember what you've learnt. If you can afford to do it in the evenings over a year, look at a local college - they probably run a class in it. If you haven't got time for that, be absolutely sure that you're in tip-top condition when you go, otherwise you'll start to get brain-fade and you'll end up typing in commands to the routers without actually understanding what they're doing.
If you can't get yourself a cheap Cisco router (a 2600 can go for under $50 on eBay) then install Quagga and have a play with that - the interface is almost identical.
If you want a quick, fun read, get Todd Lammle's CCNA book by Sybex. I used that in addition to the CCNA Official Exam Certification Library by Wendell Odom, a couple of 2600XM routers and a couple of 2950 switches from eBay.
Be wary when you go on those bootcamps that they will often use simulator programs like Packet Tracer, which will not run the full IOS command set, rather than real equipment (makes sense for a training centre as the purchasing and operational costs of Cisco gear is expensive).
As one of the other posters recommended, you can't really do switching in emulators like Dynamips as switching is performed in hardware and can't be emulated.
If a course cost you (and you personally I mean) AU$5000, you could build a CCNA lab which would be suitable for a CCIE lab - however, this only makes sense if you have to flip the bill rather than the company :).
i am preparing for my CCNA exam,the book i am using is Cisco Certified Network Associate written by Richard Deal,published by McGraw Hill.
It really depends on your initial understanding of topic. If you are preparing for ccna routing and switching, i recommend two very easy and understandable books
a) ccna routing and switching by example by M irfan. you can find this at amazon
b) ccna routing and switching by todd lammle.
these two are enough for your understanding. I loved first one