Hi,

It is pretty straight forward. Just put the personal blog in a subdirectory. I would put a link to it in the top menu, or in the side bar.

It would require some knowledge of php to get the recent posts of the second blog in the side bar of 1st blog. You would probably have to tweak a plugin like recent posts, to call posts from the blog in the subdirectory to dispay in the main blog.

Main blog

Where We Relax - Relax and Refresh with Us

Secondary blog (this is a test blog for a friend, so I do not link to it from anywhere)
this is in a subdirectory of we-relax

Three Sisters » Art Gallery and Health Center - Clallam Bay Washington