Free book reviews are not free of effort, of course: you'll have to work especially hard to get your work noticed by the magazines and periodicals that really count: Publisher's Weekly, Library Journal, etc. Also remember that reviewers often work from bound galley proofs, i.e. they require your novel or new collection well before the publication date.
You'll want to send out review copies to everyone who can put in a friendly word — colleagues, community magazine, local newspaper, poetry magazines/ ezines that favour your style — but how do you reach the big boys, the literary editors of national newspapers and literary magazines? You send them a press release. Describe your book and why it is worth reviewing. Include contact information: phone, fax, email, company URL, and name(s) of personnel who can be contacted for more information. Plus how to obtain a copy of your book (simply phone, fax, email us on . . .)
Free book reviews entail considerable cost, especially in mailing copies abroad, but you'd be wise to send out as many as possible, providing only that there's some reasonable chance of the review appearing (reviewers won't promise) and that the review will actually help (i.e. is by a prestigious publication). Remember:
A few references, several illustrating the problems the self-publisher faces: