Here I have given all the information I know about Infosys test(based on sixth july exam).
Go through books and websites in the following order:
1.BrainTeasers by George summers.
2.Become a member of www.brainvista.com and go through the puzzles and answers available in it. This one will be very useful for you because it has a variety of puzzles (about 600 in number with detailed answer).
you can also submit puzzles to them.Some puzzles in the books specified here can also be seen here.
3.Visit www.englishclub.com (contains very primitive information yet interesting)and click to grammar link in it.It will be helpful for you to test and improve your gramatical skills to some extent.
4.Puzzles to Puzzle You & More Puzzles by shakuntalaDevi(2 books).
5.Brain teasers by RaviNarula.
6.Barrons GRE for problems and vocabulary(easy one not that tough as in Barrons).
7.Go through any material for Comprehension(little effort is enough in this one).
8.Go through any dictionary of confusables(like advice - advise, Martial-matrial etc).
9.If you are not an English medium student WREN&MARTIN
High school english grammar (Tenses)will help you.
I came to know of these information only few days before the exam it helped me a lot to crack. Ask any one who has taken the test to confirm the information.
No need to try anything else to my prespective.
The information given here is lot more than enough to crack infy written test.