Read here for important info.
http://www.activeboard.com/forum.spark?forumID=35386&subForumID=67230&action=viewTopic&commentID=3597521&topicPage=

As for your question, its been a long time since i last used RB, so im not sure how to do this.

Try something like:

url = "http://www.google.com/?search&q=" & textbox.text


You would need to replace the spaces in the text box with + signs.

Hope this helps!