H.H. Scullard in History of the Roman World: 753 to 146 BC has an excellent summary on the foundation legends of Rome.
Searching for more, I was rather disappointed about the quality of general information, but I found two books by T. P. Wiseman:
One can be previewed in Google Books: Remus: A Roman Myth (Cambridge University Press 1995), and purchased at Amazon.com.
There are two Bryn Mawr Classical Reviews: 97.05.18 reviewed by Nicholas Purcell and 97.06.03 reviewed by John Van Sickle.
The other is The Myths of Rome, a more recent publication by the University of Exeter Press. This 2004 hardcover edition is rather expensive, however, it seems that a paperback will be published in November 2007.
Here is a Bryn Mawr Classical Review by Peter Keegan. He finishes with these sentences:
"There are many things to like about this book. W.'s powerful combination of directed historical imagination and overarching control of evidence is consistent and cohesive. His eminently readable contextualizations of complex strands of historical information allow even the general reader an entry-point into the rich story-world of ancient Rome. For the specialist and the advanced student of Rome, the meticulous, succinct, and wide-ranging critical apparatus (pp. 309-358: keyed by page number and a brief phrase to identify the relevant idea) is a treasure-trove of source material, historical method and scholarly insight. Of particular benefit to anyone interested in the portrayal of myth and history is the well-judged and judiciously-used portfolio of representational art (Colour Plates 1-16; located between pages 10 and 11). In conjunction with the extensive variety of epigraphic, archival, pictorial, narrative and poetic material drawn from ancient and post-Renaissance sources (over a hundred figures as well as a democratic selection of sources in translation), the artistic re-interpretations of Roman mythography helpfully reinforce W.'s main thesis. A time-chart (pp. xvi-xviii) listing the main literary and visual sources and the important historical and legendary events and commissioned topographical and geographical figures (pp. xix-xxii) provides useful points of reference and clarification. Particularly welcome are the brief, illuminating excursuses inserted throughout the text on shaded pages (thirty-one in all), which treat such diverse topics as werewolves, Macaulay's Lays of Ancient Rome, Lucretia from Augustine to Benjamin Britten, George Washington as the Cincinnatus of the West, public spectacles, and Sporus, slave-boy of Nero, Otho and Vitellius.
"I recommend The Myths of Ancient Rome to students and teachers of Roman history, art and myth at undergraduate and graduate level, specialists in these fields, and anyone interested in a potent and provocative re-interpretation of the Roman historical tradition."
It seems to be worthwhile waiting for the paperback.
