Lowe lab has a compendium of SnoRNA database: http://lowelab.ucsc.edu/snoRNAdb/ You could as well query and find targets using this.
A fully functionaly upgraded database exists at http://people.biochem.umass.edu/fournierlab/snornadb/main.php The target RNAs and modification sites are updated from time to time.
If you are looking at curated list, this http://snoopy.med.miyazaki-u.ac.jp/ could be an ideal one as it has a graphical view for gene loci etc.
I found three links that might be of use to you. They seem to have a decent set of documentation, as well as API's for calls using Matlab and other tools.