Here's a list, by no means complete, of companies with Zionist connections:
http://www.inminds.co.uk/boycott-brands.html
As you can see, a boycott of Israel is a difficult proposition, unless one were to live in the country and produce almost everything one needed for oneself.
That's a laudable goal, and one I try to pursue, but it won't impact the current situation.
Perhaps a better way to boycott Israel, is to boycott consumerism as a lifestyle.
1.Remove all one's money from the bank and convert it to gold and/or silver.
2.Change one's employment to "self".
3. Discover ways of creating local economic activity with people you know, through barter, cash exchanges, etc.
4. Reduce one's consumption of processed products- everything from TV programming to soft drinks. Use staples and make things from scratch. Play a board game instead of shoving a DVD into the box. Make your own clothes, fix your own car, etc.
If everyone stops spending, heck, if everyone cuts their spending by just 20%, Israel will collapse. They can't kill every Palestinian. As long as one Hamas fighter crawls from the wreckage and shakes his fist at Israel, Israel is defeated.
If you follow the steps above, you will not only help bring Israel to reason, you will save yourself and your family in the bargain, because you will be more psychologically resilient and more physically equipped to weather the economic firestorm that is about to destroy the US.