If you have records in the Meta-Share maximal format you can use the profiles and conversion stylesheets as described at the Meta site.
If you have records in the Meta-Share minimal format you can use this profile (and the generated XSD).
Then you can use an XSLT transformation to transform your Meta-Share records into the equivalent. For the maximal Meta-Share schema, guidelines and XSLT files are provided here. For the minimal MS-schema to , the XSLT is provided here.
Related to this Jozef Misutka from UFAL has been so kind to implement an OAI-PMH module for the Meta-Share repository.
See also: CMDI interoperability workshop