There are plently of resources available on the internet and in bookshops for the beginning learner. The best I have found are the Michel Thomas 'Foundation' and 'Advanced' courses, which are very cheap for what they are. The two Pimsleur cd collections are also very good, if a bit pricey. Rosettastone is good for vocabulary, but overpriced. There must be many people like me who have worked through these courses and are looking to take the next step forward. Unfortunately, there is very little available at a lower intermediate level - the HAU podcasts are well constructed, but there are no grammatical explanations or english translations to go with the podcasts, so they are not very useful; the FSI Greek course does provide extensive explanation, but is dry as bones. When I first found GreekPod I was over the moon - based on the content of the other language courses in your series, it seemed that GreekPod would fill this gap and enable me to study on-the-go whilst commuting, but it has been almost 6 months, and still no sign of any Intermediate, let alone Beginning podcasts. I hope this doesn't go the way of the ChinesePod course, and we have to wait another year before the more advanced lessons are available.
I can understand that Survival phrases and total newbie lessons constitute the 'bread and butter' of the course, attracting more attention than more advanced lessons, but I can't understand why there are so many lessons set at an advanced level ( maybe for students at university studying Greek ) with nothing inbetween.
Greatly looking forward to Intermediate content !