Hmm, the only podcast I actually listen to with any regularity is a BBC podcast and I found that through the official website... so that's not too much help.

There's the usual stuff like making the website more inviting, giving it more of a promotable web-presence. Then you can trade links with similarly themed content, not necessarily podcasts but web comics, game blogs etc. There's a particular niche that would enjoy these so it makes sense to target that.