Learn Spanish (Spain): Hoy bebemos agua sin hielo. - Today we drink water without ice.

In Spanish, the ending of the verb usually tells you who is doing the action. The -emos ending on bebemos (from the verb beber, meaning to drink) strictly means "we drink". Because of this, subject pronouns like nosotros (we) are often dropped unless you want to add special emphasis.

How do I pronounce the 'h' in hoy and hielo?

The letter 'h' is completely silent in Spanish. You should pronounce hoy exactly like "oy" and hielo like "ee-eh-lo".

Why isn't there a word for "the" before agua, like el agua?

Just like in English, when you talk about an uncountable noun in a general sense (like "drinking water" instead of "drinking the water"), you leave out the article. You can just say bebemos agua.

If sin means "without", how do I say "with ice"?

The Spanish word for "with" is con. If you prefer your drinks cold, you would ask for agua con hielo.