I decided to install Tesseract 3.03 on my Ubuntu box recently. (I wanted to have the text layer on my scanned PDFs correctly lined up with the underlying page image - Tesseract 3.03 does this.). So I downloaded the appropriate source and set about building.
I had to build and install leptonica first - I used version 1.72. There after, there was a problem with make in the tesseract 'api' directory. I resolved this by simply executing the required command by hand:
# /bin/bash ../libtool --tag=CXX --mode=link g++ -o tesseract tesseract-tesseractmain.o libtesseract.la -lrt -lpthread /usr/local/lib/liblept.a
This is just the original line emitted by the Makefile with the location of the leptonica library (i.e. /usr/local/lib/liblept.a) corrected.
Thereafter everything was relatively straightfoward. I had to download the English 'trained' data from the appropriate site, and then tesseract was ready to use.