Where is the best place to invest money for my children (1 & 3 years old) living in Belgium?

I want to invest money for my kids (like 200 euros a month). I prefer security over risk, and they won't need it till they are 18, so it is a long term investment.
Any ideas?

Wow, you have a much longer time frame. Invest in stocks/mutual funds. Aggressive funds that has a destinated year of about 2020 would be preferred. if you like to go individual stock, choose ones that has great long term potential over dividend(it would not hurt to have both).

with 100 euros each kid and 8% average return the 3 year old will get about $35,000 and the 1 year old will get about $43,000 by the time they are 18.

I start my kids right at about 5 years ago and only inject money once annually and never sell any of their stock(20-30 different company using Sharebuilder.com). Their portfolio is nearly double to date about 7% average. If another bull market hit in the next 8 years, they will average a lot higher 15 -20% annually. by the time the first one turn 18, I expect to see the portfolio grow by 4 or 5 times.

Good luck to you and your family

create your own website, good for long term goals or you can join home based business if you dont want to leave them.

1) Pay the monthly sum into in a high interest, tax exempt, bank deposit a/c.,similar to ISA's in UK.

2) At the beginning of every year, use it all to buy shares in a blue chip co.

3)Do the same every year, buying a different blue chip co., in a different market sector.

Blue chip means a large, solid, market leading, co., like Shell, HSBC, Glaxo, etc. By the time the children are 18, they will have a good diversified portfolio of 15 - 17 different shares, giving them a safe, rising income and capital appreciation. Do not buy and sell, buy and hold. I assume you want to be an investor and not a speculator.