Hello,
I thought I'd share this quick tutorial for creating inkjet-safe halftones using only adobe illustrator
The image i have created here has:
--- 100% black Text
--- 50% black plant image
--- A Gradient from 100% Black to 0% Black
Step 1. Open your illustration you need to halftone
Step 2. Select the items you need to turn into halftones
Step 3. Select
Effects --> Pixelate --> Color Halftone 
<--- Click to enlarge
Step 4. Enter a number into the top line (shown highlighted in the photo) the lower the number, the finer the dots will be

<--- Click to Enlarge

<--- Click to Enlarge
Step 5. Print to your Inkjet Printer!
NO EXPENSIVE RIP SOFTWARE NEEDED!!!!
Here's some crappy cell phone shots of the final output:
Extreme Closeup!

<--- Click to Enlarge

<--- Click to Enlarge

<--- Click to Enlarge
This page was printed on an Epson 1270 using the stock Mac OS X drivers on plain paper.
Output quality was set on high