Todd Lammle's Sybex booked is what helped me the most. Lammle also wrote a piece of software called RouterSim that would be very beneficial. At least I thought it would. I had a demo. The demo didnt do much for me because it limited the softwares abilities. No config mode. But the fullfledged app not only gives full router functionality (2600 series I think) but it allows you to work on 3 router interfaces at once and has walkthrough lessons. I would have loved to have had it, but the Sybex book was enough to pass in my case, although I did fail it the first time by a question or two. (748, needed 755. 880 or something like that the second time)
Word to the wise. If you think that you can pass the CCNA easily because you passed a couple of MCSE test then you are only fooling yourself. The Enterprise test was fairly difficult but no Microsoft test comes close to the CCNA. That is only my opinion based on my experience but the test is not easy. The exception to that would be if you had alot of Cisco router experience of which I had zero when I took the test.