d sounding like v?

Hi there, I've just started learning spanish and are on the lession 1 audio mp3's. It's great fun and I'm definitely enjoying it. Whilst listening to the audio's, sometimes words such as Disculpe sound like they are said with a 'v' at the begining (i.e. visculpe) instead of a 'd' but in other words the 'd' is as in english. Additionally I noticed that sometimes Mauricio says it with a 'v' then Amy also says the same word after but pronouncing the 'd'. Is this like the 'v' and 'b' where they sound similar or just the way it is in different parts of the country. I'm just a little confused and want to make sure I'm saying everything right. Thanks, Rich

The "d" sound in Spanish is pronounced like the English "th" in "mother", "father"...So it may sound a little bit like a "v" at times.

Thanks that's great. I did think as much but wanted to make sure. Rich