hi,
i am tryin to interface an lcd(16*2) with duemilanove,i dont see the anything being displayed in lcd except the blocks which appears wen u just power the lcd, i guess the problem is current, can some one tell me what is the exact problem, and also hopefully the solution.
Another think to be careful about is the contrast, the LCD I have is VERY sensitive to contrast and depending on the number of lines you use, it can be either too dark (only blocks are visibles - like you have) or too weak/unreadable. Use a variable resistor to tweak the contrast.
Otherwise, even if I power my arduino with a simple battery, it's working, I doubt that it's a current problem ... But it may vary between different models.