add some mods to MS SQL server SSAS OLAP cube

We have a running MS SQL server 2005 with several analysis services cubes. The cubes are created via MS visual studio 2005. Mainly connected via excel 2007 to analyse the data. Data consists is about 10GB over about 100 different tables. We would like to do several things; - make some minor corrections in a few calculated fields - add some columns to one of the the major tables. - add some new calculated elements profound knowledge of SSAS Olap design required. Please show profile/references to previous work in this field. Further details after comment/bid.