When you Publish a Blog you may need its Permailnk / URL to Link it on to one of Your Custom lists on your space or Create a Guestbook.

This is How you get the Permalink:

• Publish your Blog Entry.
• Go to "Preview" Mode by clicking on 'Preview My Space'
• Navigate to the Blog you have Posted.
• At the Bottom of the Blog entry, there will be something like : 

• Click on the Permalink to get the permalink link of your blog entry.

•  Right click, Copy..

Now you can use this URL to direct or link it anywhere on your Blog.

Thanks Dev