Since my experience is primarily in molecular and computational biology, my opinions are obviously biased towards those fields. I have worked in both academia and industry (i.e. >15 years of "Science" experience with 9 years at the PhD level). In my opinion, you should be concentrating on these science skills in upper grade level high school (11-12 grades, preferably just 12).
1) Really get to know MS Office or some other package of word processing (with references support, like Endnote), spreadsheet, and presentation software. You will need a good understanding of the word processor to write grants, reports, and manuscripts. A good understanding of the spreadsheet to organize and analyze your data, with special attention on doing correct statistical analysis. A good understanding of the presentation software for ... presentations. Macs or Windows since it doesn't matter.
2) Really know how to use websites such as http://www.ncbi.nlm.nih.gov/ and http://expasy.org/. The biological science world revolves around biomolecule and biopolymer databases. Then, make them find manuscripts in http://www.ncbi.nlm.nih.gov/pubmed and evaluate them. They also need to learn to evaluate the quality of the information that they find.
3) Make them do journal club. That will hit all levels of Bloom's taxonomy, is student-centered, and buzzword compliant!
Other skills that maybe useful:
3) Entering, searching, and retrieving information from a SQL-like database. Oracle, MySQL, or PostgreSQL servers are everywhere in both academia and industry. Maybe industry has enough resources to create a frontend for their scientists, but most likely they will have to wait for the comuputer analyst group to provide the data you want. Better to ask for read access and do it yourself. Any operating system can be used to access the data. MySQL and PostgreSQL are well supported in Linux.
4) Industry is moving to Lab Information Management Systems (LIMS) and large data generating academic labs are also using LIMS. I don't know if there are free/low-cost LIMS software available, but this would be extremely nice exposure considering most universities won't have such a system for undergraduates. Most LIMS are web-based so it really doesn't matter about the front-end. The back-end is probably Linux or Windows Server.
5) In academia, knowing Linux/Unix/BSD is very useful as most academic software packages are made to run on a Unix-like OS. MacOS X support is actually pretty decent for academic software due to its BSD underpinnings. CygWin is a must if you want to run on Windows. Academics program for the computers that they have, and they mostly have Macs and Unix-like systems.
5) Programming languages that are used extensively by computational biologists are C/C++, PERL, PYTHON, JAVA, and Fortran (more legacy now). From what I saw, PERL and PYTHON dominate on the bioinformatics side.
As for hardware/OS...
For computational biology or computers in biology, Windows is winning that market share. Macs are pretty much only found in academia and mainly for MS Office. They can be used as front-ends obviously, but the general trend of specialized software is to run on XP, for now. I don't know how many science software developers have moved their code to support Win7 natively, but probably not many as these companies are rather slow in adopting new tech. Still, obtaining these licenses is pretty much impossible for a high school. I doubt even the district could find the budget for them.
Setting a Linux cluster for computational number crunching is seen very often in academia and probably in industry, too. So, maybe you can salvage some of the older computers and turn them into a small computational cluster. However, setting up things like this may be impractical with your IT department...
Overall, I think it is very ambitious to provide "real world" science and engineering experience at the high school level. Leapfrogging 4-year university experience, when that is currently required even for an entry-level laboratory technician position, seems to be putting the cart before the horse. True, the university experience is not even close to the "real world" either, but I think interning or setting up summer research jobs in university labs would provide a much better experience than a high school course, unless that high school course is setup like a university lab. Your IT department may not allow any of this and if they did, they probably couldn't provide support.
Help the students build a solid foundation to carry them through life, whether or not that includes undergraduate or postgraduate education.