[CentOS] trying to understand OSS, GPL, BSD & other licensing model for software distribution.

Hi all,

We are busy developing some software (some is web based, others not)
and I am having a bit of hard time understanding (or rather, choosing)
a license model to work with, We will offer some free software (PHP
based scripts, and even Windows based applications) and for this I'm
sure the GPL, or even LGPL (for the network side?) will work fine.

But, we also need to suppose these scripts, and will be charging for
support (other for installations, customization, or even custom
derivations, etc), but at the same time we need to distribute some
commercial software to cover developer's salaries, rents, marketing,
business growth, etc.

Now, my question(s) is as follows:

Can I sell one script as GPL, but another as AGPL, or even BSD under
the same company name? And if these 2 are tied together (i.e. being
able to be used together, although seperate programs / script - for
example Apache + PHP), how would I license them?

We are writing a series of PHP + MySQL based scripts which can be used
on the internet, either stand-alone, or in conjunction with other
scripts (API driven), and I want to offer a free, limited edition, as
well as commercial edition with more features. We're also writing some
software that makes use of MySQL / sqlite / postgresql, and even
MSSQL, so I need to take their licenses into consideration.

What would be the best license for this? I know it's broad, but
there's just too much to readup on the different licences and I've
read a lot already, not knowing where to go. I have a feeling that I
may need to go the dual / multi-license route, but even then I don't
know which licences to use.

The open source projects wouls also be open for other people to add
their own modifications, but I would also like to allow others to
write commercial addon's as well.

Any pointers, and even past-experiences?

-- 
Kind Regards
Rudi Ahlers
CEO, SoftDux Hosting
Web: http://www.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532