Free Conference - free web conferencing service
For teleconferencing, use +1-218-936-6666 (U.S. telephone number) free of charge. Note that long distance charges will apply. But you can buy a phone card at your nearest gas station and use it for North American calls. A $5-dollar card will usually give you over 300 minutes (we use Apple). If you are doing online training, buy a phone card for each user and send them PINs by email. This will keep your teleconferencing costs down, at the negligible level.
This site provides free web conferencing tools. The service is good and the interface is very nice, but the latency is quite high (users experience delays). For a full service with all features, they charge $9.95+ per month, but their standard package is free. Note that you will also need a teleconferencing service to conduct a webinar online, for example (see the link above).
Mikogo - free web conferencing service
Oyur favourite free web conferencing and online meeting tool. No latency, great service, but the site goes down occasionally for maintenance.