Estimating software development effort is an important task in the management of software projects. The task of effort estimation is challenging and is an important area of research in the field of Software Project Management. A number of estimation models exist for effort prediction. However, many newer models are still being proposed and researched upon to obtain more accurate estimations. The development of software has always been characterized by parameters that possess certain level of fuzziness. This requires that some degree of uncertainty be introduced in the models, in order to make the models realistic. Fuzzy logic techniques come to play in such a situation to tackle the uncertainty issues. Besides, fuzzy logic had been combined with algorithmic, nonalgorithmic effort estimation models as well as a combination of them to deal with the inherent uncertainty issues. The primary purpose of this paper is to review the studies carried over the years for estimating the software development effort using Fuzzy Logic Techniques in order to improve prediction accuracies. In this paper we have also tried to propose a novel fuzzy logic based framework to estimate the effort at the early stages of software project development. The paper discusses the theoretical foundations and concepts for the framework and in subsequent publications we will be discussing the results obtained from our ongoing experimental work.