Starting a Company Blog is easy. The major blog software providers offer free software that can be implemented in minutes. I recommend Blogger.com (owned by Google). To learn how to use the Blogger.com system, I suggest purchasing the book "Publishing a Blog with Blogger: Visual QuickProject Guide (2nd Edition)" by Elizabeth Castro. It will tell you everything you need.
If you want your blog design (or “look”) to match your corporate branding, you will need to hire a graphic designer to create a blog "skin" that you add it to your Blogger.com account.
However, there are some hidden risks you should consider before starting a blog for your firm.
When you add a page to your blog, it is called a "post." Each "post" has a date. If visitors go to your blog and see that it has not been updated in a long time, they assume something is amiss. Why hasn’t your company updated your blog in X months? Are they no longer functioning?
A blog is just like a newsletter. If publication of your "newsletter" suddenly stops, people wonder why.
Many blog writers have difficulty generating topics for their blog. As with any newspaper or newsletter, your staff needs to establish an editorial schedule before the blog is published. Regular editorial meetings to decide topics must also be held.
Blogs can consume a great deal of your staff time without translating into a return on your investment. While it is good to use a blog to establish good will and an open communication with your customers, you need to assure that the amount of staff hours you spend on a blog translates into revenue for your firm.
Instead of starting a new blog, consider reaching out to Influential Bloggers in your industry (professionals who already have a blog up and running).
I have established corporate blogs and have managed blog writers. I also give recommendations on how to best get the most ROI our of your blog effort.