I do this all the time and 8 times out of 10 I get ranked on page 1 of Google in around 5 minutes.
I'll explain this step-by-step so you can see exactly how I do it.
I start by going to the PRLog.org website (prlog.org) I like PRLog as you don't need to wait for your press release to be approved. They're all approved instantly.
Fill out your info and click on "Create Account".
Once you've registered an account and you've logged in, click on the "Submit Press Release" link.
You'll then get to see all the great features you get for free.
Click on "Next" at the bottom. Now you'll be asked to submit your press release.
Enter the keyword phrase you want to rank for as the headline (min 20 characters).
Note: Ideally you want to go for low competition long tail keyword phrases (more than 3 words) where there aren't any authority sites on the first page of Google.
If you use Google Instant you can easily find low competition long tail keywords. If when entering your phrase into Google you see sites such as Ezinearticles and other article sites or classified ad pages or Hubpages or Squidoo etc..then you shouldn't have any problem ranking.
Enter the image text and then click "Next". Then enter your press release summary, body text (make sure you include a link to your website!) and choose an appropriate category. You can enter upto 3 categories.
Next to "Issued By" enter your name or company and enter your email below. You also have the option to upload an image.
You can also enter additional information such as tags, company profile etc.
At the bottom of the page click on "Go To Final Step".
You can now preview your press release. If you need to change anything click "Modify Press Release".
If you're happy with it click on "Submit".
Now, here's the exciting bit.
Go to Google and type in your keyword phrase. Refresh the results every few minutes and you'll see your press release appear in the top 10.
I've never had to wait more than 15 minutes for a PRLog press release to be indexed and ranked on the first page. Sometimes you'll find your press release ranking on Google's first page in as little as 2 minutes. Most are indexed AND ranked in 5 minutes on the 1st page.
PRLog press releases are also shown in Google News too which can bring you some good traffic.
This works great for ranking local search terms too. Many times I've ranked in the top 3 in Google in minutes for local keywords.