Hi, Olan. Welcome to Apple Discussions.
-Does upgrading the memory from 256MB to 640MB make the computer much faster?
You will see a speed increase. How much of an increase you will see depends on which applications you use. It won't be nearly as fast as a new computer.
-Does Airport Base Station really needed to be able to have wireless connection when you have Airport Card in your PC?
No, you don't need an Apple Airport Base Station, but you do need some sort of device to provide wireless connectivity (when at home). This can be a wireless modem, wireless router, or wireless access point. Such a device is wired to the internet and transmits the signal to your computer's AirPort card.
-Can I also upgrade my Mac OS X 10.2 to a higher Mac OS?
Yes. You will not see all that OS X 10.4 can do with a G3 processor, and I doubt that upgrading to OS X 10.5 (when it is released this fall) will be possible with a G3 processor. I have kept my G3 800 MHz iBook in OS X 10.3.9 (but others are happily running OS X 10.4). The less you know about hard drive and OS maintenance, the greater hesitancy I would have in recommending anything above OS X 10.3.9.
-Can I also use my iBook g3 to have a parallel desktop? having 2 OS in my Mac iBook like windows and Mac OS?
You can have Mac OS X and Mac OS 9 on your G3 iBook and boot into one or the other. You cannot use Parallels to run Windows on a Power PC-based Mac. You need a Mac with an Intel processor (like the
MacBook) in order to do that.
-My battery lasts for 1 hour, does it mean i have to replace my battery for this unit?
Only if one hour's worth of battery life does not meet your needs.
http://www.apple.com/batteries/notebooks.html
I really need your practical advice before i made my move thanks very much.
My advice is to upgrade to a new computer if you can afford it. The hard drive of a new MacBook will be (at least) twice the size; it comes with OS X 10.4; you will have 1 GB of RAM (at a minimum — I would increase that to 2 GB at the time of purchase); wireless connectivity and Bluetooth capability are built in (you still need the wireless access point, though); the processor is three to four times faster (at least); you will have a new and improved battery; there is a built-in iSight camera; you will have the Windows capability you asked about. It is such a spectacular upgrade. By the time you buy a RAM module, original AirPort card, and upgrade of the OS, you are well on your way to the purchase price of a new computer, and you would still be far behind where you would be with a new one.
There, you have it.
You're welcome.
