I don't have a table saw or a router or anything like that. I do have a circular saw, and a drill. I could probably justify buying a tool like a Kreg Jig or something like that for this project.
Congratulations on building your own book case. Here are a few tips.
Get a good large framing square. This tool will help you scribe square guide lines and also can be used as a guide for your circular saw to cut nice straight and square pieces of wood.
Use tiny head, counter sunk finish screws and wood glue to secure the pieces.
Make the bottom and top horizontal pieces full width. Fit the vertical upright pieces between them. Fit the shelves between the upright pieces.
Carefully measure and scribe the bottom edge location of your horizontal shelves on the vertical uprights.
Clamp a straight guide to these lines to help align the shelves to your lines before securing them to the sides.
Drill and countersink pilot holes for your screws so you won't split your wood.
Use glue on all joints.
Install a back or at least small 90 degree triangle pieces of wood or thin plywood on the back four or any parameter corners to assure your case doesn't rack or lean sideways when loaded.
Measure twice or three times, then cut once!!!
Fill your screw holes with lightweight spackle, sand smooth, prime, paint and enjoy.
This website has a ton of DIY furniture plans aimed at people who only have basic tools. Some of them require a compressor and a finish nailer, but you can probably work around that. (Although I've found that my compressor has been an extremely useful tool around the house. You may want to look into buying one if you're going to be doing more projects. A lot of times you can find them bundled with a brad nailer too.) My wife has a list of about a dozen projects from that site lined up for me to do.
Here's a good example of some bookshelf plans with a materials list and step-by-step instructions. I'm not sure if it's the exact style you're looking for though.
another sawing tip - if you can, score yourself a table saw or goto home depot or lowes - they'll cut large pieces for you down to size; set the fence once and make as many cuts as you can at once so their all the same. with cubes, as i'm sure you'll be stacking them / putting them next to each other, you'll want them to all be as close to the same as possible; constantly re-measuring and readjusting the fence will make inconsistent cuts. even if their off by a 1/8th or a 1/16th, you'll notice it when their stacked / side by side.
honestly, by the time your done buying the wood / making the cuts / painting or staining, you may as well go get it from Ikea - i know exactly what your talking about and they have a nice collection of stuff like that. I'm all for doing stuff myself, but i'd be to anal about them coming out right and lining up properly.