Well, the most accessible English translation is in The Fathers of the Church series from Catholic University of America. Wagner included the "Long Rules" in her collection of Basil's works called (surprise!) Ascetical Works
. Here's the bibliography entry:
Basil, Saint. (330-379). "Long Rules," in Ascetical Works
. Translated by Sister M. Monica Wagner, C.S.C. The Fathers of the Church, vol. 9. New York: Fathers of the Church, Inc., 1950.
CUA republished it in 1999 as a paperback. Neither the hardcover nor paperback are available on amazon, so you might need to high-tail it to the library. Fordham's Medieval Sourcebook is supposed to have an online version, but, as far as I know, still hasn't put it up (perhaps copyright issues).
Otherwise, both the long and short rules are readily available in Greek and Latin (an early translation by Rufinus) in Migne.
Here's a bit about them fromhttp://www.catholicity.com/encyclopedia/b/basil,rule_of_saint.html
Under the name of Basilians are included all the religious who follow the Rule of St. Basil. The monasteries of such religious have never possessed the hierarchical organization which ordinarily exists in the houses of an order properly so called. Only a few houses were formerly grouped into congregations or are today so combined. St. Basil drew up his Rule for the members of the monastery he founded about 356 on the banks of the Iris in Cappadocia. Before forming this community St. Basil visited Egypt, Palestine, Coelesyria, and Mesopotamia in order to see for himself the manner of life led by the monks in these countries. St. Gregory of Nazianzus, who shared the retreat, aided Basil by his advice and experience. The Rule of Basil is divided into two parts: the "Greater Monastic Rules" (Regulae fusius tractatae, Migne, P.G., XXXI, 889-1052), and the "Lesser Rules" (Regulae brevius tractatae, ibid., 1051-1306). Rufinus who translated them into Latin united the two into a single Rule under the name of "Regulae sancti Basilii episcopi Cappadociae ad monachos" (P.L., CIII, 483-554); this Rule was followed by some western monasteries. For a long time the Bishop of Caesarea was wrongly held to be the author of a work on monasticism called "Contitutiones monasticae" (P.G., XXXI, 1315-1428). In his Rule St. Basil follows a catechetical method; the disciple asks a question to which the master replies. He limits himself to laying down indisputable principles which will guide the superiors and monks in their conduct. He sends his monks to the Sacred Scriptures; in his eyes the Bible is the basis of all monastic legislation, the true Rule. The questions refer generally to the virtues which the monks should practice and the vices they should avoid. The greater number of the replies contain a verse or several verses of the Bible accompanied by a comment which defines the meaning. The most striking qualities of the Basilian Rule are its prudence and its wisdom. It leaves to the superiors the care of settling the many details of local, individual, and daily life; it does not determine the material exercise of the observance or the administrative regulations of the monastery. Poverty, obedience, renunciation, and self-abnegation are the virtues which St. Basil makes the foundation of the monastic life.
As he gave it, the Rule could not suffice for anyone who wished to organize a monastery, for it takes this work as an accomplished fact. The life of the Cappadocian monks could not be reconstructed from his references to the nature and number of the meals and to the garb of the inmates. The superiors had for guide a tradition accepted by all the monks. This tradition was enriched as time went on by the decisions of councils, by the ordinances of the Emperors of Constantinople, and by the regulations of a number of revered abbots. Thus there arose a body of law by which the monasteries were regulated. Some of these laws were accepted by all, others were observed only by the houses of some one country, while there were regulations which applied only to certain communities. In this regard Oriental monasticism bears much resemblance to that of the West; a great variety of observances is noticeable. The existence of the Rule of St. Basil formed a principle of unity.