I need a tool for testing a microRNA's targets for enrichment of KEGG pathways and GO terms. I know the R package CORNA ( http://corna.sourceforge.net/ ), but unfortunately it was built before R 2.10.0
I would suggest you to use miRWalk database (http://mirwalk.uni-hd.de). Because, this database offers a comparative platform of possible miRNA-target predictions using 10 different data sets i.e. miRWalk, Dianamt, miRanda, RNA22, miRDB, TargetScan, RNAhybrid, PITA, PICTAR4 and PICTAR5.
I would suggest you to use miRWalk database (http://mirwalk.uni-hd.de). Because, this database offers a comparative platform of possible miRNA-target predictions using 10 different data sets i.e. miRWalk, Dianamt, miRanda, RNA22, miRDB, TargetScan, RNAhybrid, PITA, PICTAR4 and PICTAR5.
There are number of bioconductor tools and I suggest that is the best place to start with. Any way I will give you some links here and check them out. It is also better to use BSGenome package where you can write your own codes to analyze miRNA mainly the coordinates and surrounding areas in a quite efficient manner.
Some of these packages are not relevant to you but if you look at the examples some times you might find a way around to use some of these packages to answer you questions or to design ideas for your problem oriented scripts.
As Mick said most of the tools are mainly organism oriented or a particular question specific, but the beauty is that they provide enormous amount of ideas as to how one could tackle problem in hand in a creative manner.
DESeq is a tool to perform normalization of RNA-Seq libraries and identifying differentially expressed genes and EdgeR does more or less the same, but produce different results some times. It is not that they disagree in producing different sets of DE genes, but differences in number of genes differentially expressed.
So they could be used to analyze differentially regulated miRNA, but it depends on whether your sequencing approach cover total transcriptom, total miRNA or a subset of miRNA I think, since both of these tools try to address reasons behind libraries with different sequencing depths and resizing the libraries to obtain realistic profiling of the expression levels.