It will be hard to bump up the iCab speed because modern websites are resource hungry. You may get some better performance by making sure that your application is reserving as much RAM as you can afford to give it. Here is a link to the Apple's instructions on assigning application RAM in OS 9.

1. Quit the application if it is open.

2. Locate and click once on the desired application icon on your Macintosh hard disk (not the icon in the Launcher or an alias to the application).

3. Choose Get Info from the File menu.

4. Make sure the Kind: is application program and not folder, alias, or document. If it does not say application program, there is no Memory Requirements area.

5. Select Memory from the Show pop-up menu.

6. Increase the amount of memory allocated to the application in the Preferred Size box by 25 to 50 percent. (Example: change 1000 K to 1500 K)

7. Close the Get Info window.

As for a future upgrade, you will probably want to consider two key elements. Are you willing to buy new applications and do you own any FireWire devices? If you have OS 9-based applications that you must bring over because you do not want to upgrade the software, then you should focus on a used computer with Mac OS 10.4 Tiger installed. This does not include general applications like email clients, web browsers, and basic iLife applications. Those kind of applications will come on a new system, but if you have software that was never written for OS X, then you need to have the Classic application support that is in Mac OS 10.4 but missing from Mac OS 10.5 Tiger.

If you are willing to leap fully into the modern Mac OS and applications, then definitely the new Unibody Macbooks will be right for you and should last you for many years. Unless you need an ultra light computer, steer clear of the MacBook Air and look at the mid-range MacBooks. They are heavier but will have more processor power and storage. The MacBook and MacBook Air both don't have FireWire, so if you have a FireWire-based device you will need to look at a MacBook Pro.