I've gotten several queries about where to get the parts I used in my electronics projects. Although they are generally not too difficult to find, knowing where to get electronics is not exactly intuitive. Unfortunately, most of these parts are not available at common electronics outlets. Forget about trying to find specific ICs or even something simple like resistors at so-called "consumer electronics" chains; they only sell big-box items like televisions and stereos. Many people try Radio Shack, and this is a better choice; at one point in time, Radio Shack actually had many electronics parts in stock (and could special-order things you needed that weren't available right on the shelves), but in more recent times, Radio Shack has become more interested in selling "consumer electronics" as well. (I keep putting this phrase in quotation marks because although it is the standard term, it simply makes no sense; people who buy capacitors and diodes are consumers too.) If you're lucky enough to live in a place that has a Fry's Electronics outlet (which is pretty much restricted to certain parts of the United States), at one point in time you had a great source for almost everything electronic, but with the downturn in the computer industry, Fry's, too, has shifted their focus away from things that real people use, and more toward silly items that interest only boring people, like music and movies.
So where's a person to turn? Generally, my advice is to forget about trying to find electronics locally. Assuming you live near some reasonably populated urban center, you can probably get resistors from somewhere nearby, as well as basic tools like soldering irons, but as soon as you get to ICs, everything just goes out the window and you'll probably have to buy through the mail.
Almost any decent electronics supplier is likely to have a website where you can search for parts these days. I got most of my parts for my projects from Jameco, which is a good choice for this kind of thing because they tend to cater more toward the hobbyist market. As such, Jameco is more than happy to serve people who only want to order one or two of an item, as opposed to industrial suppliers who are used to orders with quantities in the thousands. As I write this, you can still place small orders with Digi-Key and Mouser, but both of these companies have recently ballooned to sizes much larger than their comparatively humble beginnings, and they may stop serving hobbyist or residential customers at some point in the future. I haven't yet dealt much with Newark, so I'm not able to comment on their service or pricing competitiveness, but they are definitely a large-scale distributor; their catalog is by far the largest of the companies I've mentioned (it is actually thicker than all but the very largest of phone books). Although you probably won't need them for any of my relatively small and simple projects, Avnet seems to be a good source for more specialized high-end electronics. You might also check All Electronics, which seems to be a popular source for some folks.
So now you have some choices and a few places to explore. With all that said, however, if you're new to electronics you may just want to stick with Jameco's offerings, since they're more likely to carry and stock things that would interest a person doing things on their own rather than a person who's running a large-scale electronics manufacturing plant. With this in mind, below I've listed the main parts I've used in my projects that I have listed on this website, as well as their Jameco part numbers. Hopefully this will give a boost to those of you who are looking for these parts.
6502 CPU 43191
Z80 CPU 35561
2865 EEPROM chip 40475
6522 I/O chip 43254
4093 Schmitt-trigger NAND-gate IC 13400
74LS138 3-to-8 decoder 46607