1) Free Online British Citizenship Practice Test, this is the most useful test practice site I found. You first pick 6 to 72 questions for a practice test. I suggest you use 12 or 24 questions. After you finish and submit your answers, the testing page displays your scores and gives advices on places you should improve. You can always choose to take the same test again. Moreover, it tracks the test time for you to tell whether you need to speed up in the actual test.
2) The British Citizenship Test for iPhone/iPod. This is an extremely useful app which lets you have practice test on your iPhone or iPod Touch. You can study or take practice tests any time and anywhere you like, even just before getting into the exam room. Highly Recommended.
3) The official book for the “Life in the UK Test” is what you need to pay attention to. So remember to read it before you go for the test. Usually, it costs some pounds to buy a copy of the test book. However, you can still read some free version from a few sites, such as this site 1 and this site 2
4) Key points to memorize by Jitendra Patel
Other Citizenship tests:
Canadian Citizenship Test Online for people applying for citizenship in Canada Also there is an iphone version: Canadian Citizenship Test on iPhone: iCitizenship – Canada.
United State Citizenship Test: For applicants of American citizenship.