Ho Chi Minh City is the springboard to the Mekong Delta area, approximately 2 hours by road South of the city and the plethora of booking agencies in the Pham Ngu Lao area offer one, two and three day trips. The trips offered are basically all the same so you might want to shop around for the best price.
The mighty Mekong River, rising from the foothills of Mt Kailash in Tibet, flows through China, Myanmar, Thailand, Laos and Cambodia before it reaches Vietnam, where it divides into nine river mouths, traditionally known as 9-Dragon River but which the world knows today as the Mekong Delta.
The delta area is inhabited by more than 25 million Vietnamese, mostly farmers, who grow the bulk of Vietnam's rice. Numerous natural and man-made canals serve the local traffic away from the main river which can be many kilometres wide at the end of the rainy season. Anyone who has crossed the Mekong on their way overland to Cambodia at that time of the year can attest to its greatness.
Literally dozens of operators offer almost identical tours of the area which vary from 1 to 4 days. The tours give you the opportunity to appreciate life in the Vietnamese countryside and in this unique delta area. You will visit Mekong market towns such as My Tho, Vinh Long and Can Tho in a variety of river vessels, passing floating markets and sampan villages. You can visit a coconut farm, candy producing and rice paper factories and have lunch in a fruit orchard. Here you can also see honey being produced, make friends with a very large but friendly local python and listen to locals perform traditional music. This one-day trip, including lunch, will set you back around US$8.
Only SaigonTourist (the government agency) currently offers tours to the Can Gio Forest which has been recognised by UNESCO as the first mangrove biosphere reserve in Vietnam. Located 50 km south of HCMC, the entire area covers 75,740 ha of a tidal, swampy ecosystem which is the home of a variety of wildlife and native fauna. Highlights include a visit to the bat sanctuary and a hike through the mangroves.
If traveling from HCMC by minibus or big bus doesn't appeal, several tour operators are coming up with new ways to see the Delta country. 1, 2 or 3-day tours are now available by fast cruise vessel, including one itinerary which will take you all the way to the Cambodian border.
Cycling is another option and a great way to enjoy the quiet country lanes and see the villagers at work in rice fields, vegetable gardens and orchards.
Another Saigon based tour operator has initiated a tour of the Delta by motorcycle which includes a stay with the local family.

And if you'd rather make your way to the Delta independently, there are also now several daily hydrofoil services from HCMC to cities in the Mekong Delta region. These ferries allow you a good view of the river and are certainly faster than getting there by road.
Further References:
The free, 2007 Editions of the on-line Cambodia and Thailand Travel Guides are now available in English. Other Travel Guides will be available in the near future.
In addition, Arikah now also features free, online encyclopedias in Dutch,
English, German, French, Japanese, Polish, Portuguese, Spanish and Swedish.