We have a new internet company, and our long-term plans are to create
a "community."  Because of the high interest in blogging, we thought
creating a blog community would be a great idea.  I am not very
familiar with blog software and technology.  Could you tell me if
there is software that we could buy that would allow us (license us)
to host the blog community ourselves on our server?  For example: 
ourcompanyblogs.ourcompany.com.  We would like to have different
templates available and have users signup within our site and then
post all of the blogs within our site.

there is alot of blog softwares out there that are free from
opensource softwares which uses php and mysql

you can go to http://www.opensourcecms.com/ look for blog sub menu for
all the blog software that are free from opensource software.

those software can allows you to let others to register and post blog.
you can tweak the software to suit your needs coz it is higly customizable

i can help you implement the blog system that you like using open
source software with the domain name that you like.

contact me if you want help from me

You can find one good bloger and much more at www.draft.ro/blogger.
That solution is developed by All4web Internet Solution link
www.all4web.ro and is for sale.

Good luck !