but the last time I did this I was in school and didn't do anything over the internet.

Ouch. It's hard enough when you only have 2 years to forget how to write and submit a resume.

Tips.
1) Personal information is a no-no. Aside from name and contact details (email or phone), they have absolutely no need to know whether you are 20 or 60, single or married, white, black or green with purple spots etc.

2) Keep it to 2 pages or less. Studies have suggested (and my experience has agreed) that the average hiring manager/HR person etc is likely to spend under 2 minutes eliminating over 90% of resumes that land on their desk, and anything that can't be scanned in this time is likely to hit the bin.

3) Remember that a resume is a marketing tool. You are using it to market yourself to employers. As such, it should play up the positive attributes of your qualifications and experience, and gloss over or even ignore the less relevant attributes. Nobody needs to know that you flipped burgers 10 years ago if you're going for a tech job. (Of course if you decide to apply to McDonalds then they probably do!).

4) Recent experiences, qualifications and achievements are more valuable than old ones. So your last job should have the most detail. There are a couple of exceptions to this - eg, if you worked somewhere for 5 years, and then completed a 2 month contract, there should be more detail in the older job. Ditto for educational experience. If you have a degree, then high school experiences are irrelevant beyond listing the name of the school.

5) "I increased network reliability and consolidated floorspace requirements by analysing existing systems and re-designing network architecture" reads more impressively than "Replaced many hubs with a single switch and replaced big servers with rackmount servers."
The important thing to note here is that the sentence leads with the achievement, and follows with 'action' verbs, carefully chosen to point out your strengths (analysis and design in this example).

6) Never lie in a resume. Better to leave something out completely than to lie about it. If you get asked about it at interview, you will probably fail the interview.

7) Techies have a peculiar problem with resumes - communicating their skills with various software packages. Lots of experience descriptions like;"Coded the backend of an SQL database in C", hardly makes for an exciting 'Hire Me!' resume. The generally accepted way to deal with this is to include a brief skill set section at the top of the resume. You should be careful to ensure that this doesn't turn into half a page of industry buzzwords, pick out the most relevant and strongest skills only, and generalise where it makes sense to do so, eg "SQL administration", instead of "Microsoft SQL administration". "Office Applications" instead of "MS Word, MS Excel, MS Outlook, Lotus Notes, MS blah-di-blah-di-blah". Remember, the resume is intended to get you in the door for an interview - If they may want Oracle administration experience, being too specific may cut your chances, whereas at an interview, a combination of UNIX experience and MS SQL/postgres/mysql/any other SQL database you care to mention would probably allow you to talk intelligently enough to change their mind.