You can play with a practice test here:-
http://www.pearsonpte.com/PTEAcademi...m=practicetest
From the UKBA website:-
"In the test, you will need to demonstrate a basic command of English (speaking and listening)
at level A1 of the Common European Framework of Reference. This is a basic level, which
is judged to require 40 to 50 hours' tuition for most learners. Someone assessed at
level A1 can understand and use simple, everyday expressions and very basic phrases.
You will not need to demonstrate your reading and writing skills."
Guidance for Applicants on English Language Requirements is here:-
http://www.ukvisas.gov.uk/resources/...angrequirement
This is a very interesting FAQ document, well worth the few minutes of reading to both new visa applicants and UK based FLR and ILR applicants.
Wikipedia has a very good description of the different levels here:-
http://en.wikipedia.org/wiki/Common_..._for_Languages
Hope this helps