Free usenet access or usenet access provided by your ISP will almost always be very bad. Because it is free, the speeds will be very slow. However, if you pay for usenet, the speeds will be very fast because you are downloading from a dedicated server. Bit Torrent downloads from other users. Try Usenetserver.com Its only ~$13 per month. You get unlimited downloads will max speeds. It will be faster than bit torrent.
As for searching... Before, the only way to search usenet was to download "headers" and look through them. This was a very slow and painful process. Almost every usenet program (except altbinz) can download headers. But its a painful process so I do NOT recommend you search this way.
Because downloading Headers is slow, some great people invented .NZB files. NZB files are very similar to .torrent files. NZB files tell altbinz or newsleecher where to download the file you want. NZB files are NOT the actual files themselves. They are more similar to torrent files. They just point you to the real files. The most popular NZB site is
http://www.newzbin.com They have thousands of NZB files for you to download. However, it does cost money. FileSharingTalk actually has its own NZB section (
http://filesharingtalk.com/vb3/f-nzb-index-113/ ). It is free and has a lot of files to download. I recommend you use this method to search usenet.
While, NZB files are a great way to download, not all files on usenet have NZB files created. A good NZB site will only exist if members create and upload NZB files. If you only use NZB files and not the "headers" I mentioned earlier, you will miss a whole bunch of files (no one has the time to create nzb files for everything). This is where usenet search engines come in. These search engines crawl usenet and index all the files automatically. If you pay for and use Newsleecher or Newsbin or Grabit, they have paid built-in search. You can use this to search usenet and find more stuff. However, that does cost money. Luckily, there are free search engines you can use.
http://www.newzleech.com and
http://www.binsearch.info are two great and free search engines. I recommend you also use this method to search usenet.
If you download a NZB file and open it in altbinz (or other usenet programs) and you get errors (such as "Error: Article not found" or something similar) it is because the usenet provider you are using has bad retention. Retention is the time files last on a usenet server. A server with long retention will keep files for a long time. Free usenet providers (such as from your ISP) will usually have very short retention. Usually less than a week. That means files on usenet will only be on their servers for a few days. Then they will be deleted. So it is recommended to pay for a usenet provider and get 100 days of retention. That way, you can download files 100 days old.
Again, I recommend usenetserver.com ( Please use
http://www.usenetserver.com/?agent=filesharingtalk You will be helping FileSharingTalk). They have 101 days of retention (VERY good!), SSL encryption, unlimited download, and its only ~$13 per month. Also, they include a FREE usenet search engine to provide you will another way to search usenet.