There is a recent project on Codeplex called Simple OOXML Library - http://simpleooxml.codeplex.com - that enables the creation of Word and Excel documents using the Open XML SDK v2.0.
In the words of creator, James Westgate, the project 'provides a layer of abstraction over version 2.0 as a set of simple classes and methods to create new spreadsheet (Excel) and word processing (Word) files with the following benefits:
Static functions used to create new word processing documents.
Static functions used to paste text items into a word processing document using bookmarks and save the document to a stream or file.
Static functions to create new spreadsheet documents and to retrieve worksheet, column and row references. Get style and defined name range parts.
Create an object that can set style, color and font information in a spreadsheet and retrieve and compare style parts.
Static functions to create style parts in a spreadsheet, control shared strings and helper functions when working with spreadsheet documents
High level and static fucntions to retrieve cell and style information from a worksheet.
High level and static functions to write text, numeric and datatable based values to a worksheet. Draw borders, insert rows, merge cells and set print areas.