You don't say what os and parser you are using but if it's Windows get the Msxml core services sdk, it has a parser and lots of examples in VB
As to parsing and validation they are different. Parsing is reading input and normally contructing a node tree if the xml is well-formed, i.e. single root node,nested correctly and quoted attribute values etc. Validation is comparing the structure to a DTD or schema and seeing whether the structure matches the constraints of the DTD or schema.