Since few years miRNA has shown to play important role in therapeutic related research and also known to play vital role in controlling gene expression specifically at transcriptional and post-transcription levels. Here are some important DBs and tools related with miRNA:
miRNA Sequencing data analysis : http://tools.genxpro.net/omiras/
miRNApath( R based tool) : http://www.bioconductor.org/packages/release/bioc/html/miRNApath.html
miRWalk DB : http://www.umm.uni-heidelberg.de/apps/zmf/mirwalk/
TargetScanHuman : http://www.targetscan.org/
RNAhybrid : http://bibiserv.techfak.uni-bielefeld.de/rnahybrid/welcome.html
RNA22 predictor : http://cbcsrv.watson.ibm.com/rna22.html
miRNA predictor : http://www.microrna.org/microrna/home.do
Plant miRNA DB :http://bioinformatics.cau.edu.cn/PMRD/
miRBASE DB: http://www.mirbase.org/
Plant RNA predictor : http://plantgrn.noble.org/psRNATarget/
miRNA Interaction DB : http://starbase.sysu.edu.cn/
Sequencing based miRNA DB : http://mirgator.kobic.re.kr/
predicted A-to-I edited miRNA DB : http://microrna.osumc.edu/mireditar/
Animal, plant and virus miRNA DB : http://lemur.amu.edu.pl/share/php/mirnest/
Atlantic Salmon miRNAs DB : http://www.molgenv.com/ssa_mirnas_db_home.php
miRNA prediction on UTRs : http://genie.weizmann.ac.il/pubs/mir07/mir07_prediction.html
Idea of analysing miRNA Sequencing data :
http://www.illumina.com/applications/epigenetics/small_rna_analysis.ilmn
More:
http://www.bioconductor.org/help/search/index.html?q=miRNA+target