Add to cart text link elsewhere on site given product_id?

Given that I know the product_id for a product, is there a way to construct a link that will add the product into the cart?

For example, I wrote and published an article on another site about product_id 187. I would like to include a link that sends them to my site and automatically adds the product to their cart.

I cannot use html forms, it has to be a standard <a href style and I don't want to link to product_info page and have them click the add to cart button.

I am also wanting to do this.

I want to add a 'add to cart' button for a specific product to my front page. I still want to have a front page but want to make it as easy as possible for the customer to purchase this advertised product.

Can any one assist. I have been looking at the 'add to cart' code but am not sure how to substitute a known product ID.

Thanks

Redmonds

I am also looking for a way to insert an "add to cart" button on my html pages. I can insert the button but it doesn't work. Where can I find the code to make the button work from an html page?
I would really appreciate help on this.
Thanks,
Teresa