Advice for a beginner

Hey guys,

I've just been given a new project to design 4 x 6 die cut postcards to be used at PartnerCon in San Diego.

I've not done print design before, and all I know is that your design needs to be large. I've got that covered, as my design is resolution independent. I've been told I need to leave a quarter-inch bleed.

Here's the design:

What I'm wondering is, what format would be best for me to send off to the printers, and how would I go about setting out a border to show where the design ends, and the bleed starts.

I'm familiar with InDesign on a 'making nice PDFs' level, but I wouldn't know how to import a vector object onto a new canvas.

Let me know what you guys think, and I'd love to hear your advice. Thank you kindly!

What have you designed it in then?
If it's Illustrator then you can save as a pdf with bleed and crop marks - which should be fine.
What the all knowledgable Kate says but if you are working in Indesign, just File>Place your Illustrator / vector files onto the canvas