Java
Greenfoot - learn how to write games using Java. This is probably the best Integrated Development Environment going for youngsters learning to program properly for the first time. Thoroughly recommended. There is also a very good text book (but very expensive, unfortunately) for Greenfoot as well as an active forum for educators called the Green Room.

Scratch
Scratch - a really good place to start for absolute beginners to programming. Getting students to write a few games in Scratch over the first few weeks of the GCSE computing course gets the interest going. There are some really good video courses are as well. Try here, here or here.

Visual Basic
Visual Basic 2008 can be downloaded from here.
Visual basic 2010 can be downloaded from here.
VB forums.
Getting started with VB. From here, you'll find lots of videos, beginners guides etc. A great place to explore!
A fantastic set of lessons for complete beginners.
Many sets of tutorials are listed here. Take your pick!
Search YouTube for VB.net tutorials.
I recommend the Visual Basic 2008 Step by Step book, (and the 2010 version), both by M Halvorson. It is great for beginners and A Level students.

Pascal and Lazarus
Download the Lazarus Integrated Development Environment from here. A perfect IDE for traditional console-based Pascal as well as OO programs.
Lots of help can be found from the Lazarus web site.
Excellent videos here. These are are really good resource.
YouTube has endless resources for programmers. This series must rank as one of the best.
A complete set of easy-to-follow lessons for the novice.
Another of my favourite Pascal tutorials.
Search Google for Pascal tutorials and you will lots, like this one.
More help here.
Reference guides can be useful. Information on the standard units in Pascal can be found here.
Learning to Program in Pascal and Delphi by S Langfield is an excellent beginners book. The first dozen chapters cover classic console Pascal programming. Then it moves on to OO programming using Delphi.

Assembly code and machine code
Little Man Computer
The best simulator going. Understand how machine code and registers works using Simcom.

Miscellaneous
Make flowcharts and other diagrams quickly with Diagram Designer. Ideal for algorithms.
Ebay is an excellent source of very cheap programming books.