Odd wireless behavior
My 2007 Macbook had the oddest problem with wireless that started one day. I could connect to any wireless network, but I couldn't browse the Internet. At first I thought this was a software problem. After trying different browsers, and then finally a reload of Mac OS, I realized this was a hardware problem.
I printed out and followed the guide. Overall the replacement took me 20 minutes. No real gotchas.
Just make sure you have the proper tools. Fortunately for me I had recently ordered a Mac screwdriver set from iFixit a few months prior. I had used them to replace the hard drive on my Macbook Pro. Having the proper size screwdriver is key.