Well, I don't mean to sound like I know better than the guy in the link, nor that you haven't done your research right.

first of all:
"Since laptop computers are delicate electronic/mechanical devices that greatly differ between systems, Intel does not recommend opening or upgrading the processor in an laptop computer. If you wish to upgrade a laptop computer, you should contact the laptop manufacturer."

I just want you to know that cpu's are often a tricky situation: it's important to know which motherboard is in now. Your laptop's motherboard will only be compatible with processors that are about the same speed like the one you have now: over time, the sockets that connect the cpu with the motherboard, and thereby with the rest of the laptop, have been changed over time by Intel. this is because other things have changed aswell, like the number of times that the memory can be accessed in a second, and because the cpu needs to connect to the memory through the motherboard. You can't buy a VCR, and expect it to play DVD's. What you càn do is buying a video tape that is made better/stronger, or get one that has more length to record to, so you can record 4h instead of 2h.

So, don't expect your laptop to be a new one when you changed the cpu.

If you would decide to do this anyway, I really recommend you to go to a computer store with a repair service(small ones usually do, things like *****art will simply tell you "you're much better off buying a new one").
I've been assembling my own computers(desktops) since the age of 14, started 'programming' at the age of seven in GW-Basic(didn't really understand it then, but copied code from books to try to make own games), studied computer science at university till I got sick, worked in a repair service, been a computer store manager, have a laptop now... but I would never try to upgrade my laptops processor.

in short:
1) the speed profit will most likely be minimal, and not worth the cost
2) it will probably be hard to find a processor to fit an old machine, even for desktops
3) íf you decide to do it, let it be done by a professional: if he messes up, you can demand a replacement, instead of just not being able to visit PC anymore.

I'm sorry, I hope I didn't dissapoint you. Fast computers and the 'new' things can seem attractive, but if you just want to browse the web, check emails, an old celeron(there are many cpu's that are called celeron/centrino, but that vary much in speed) with a good old windows '98/win98SE, is certainly enough.

and for the guy in the link: hope he has a lot of luck with his 'degrees', if he doesn't know how to use Google.