I had to prepare certificates for a workshop recently and this is how I did it.
First, I prepared a border using smartdraw and called it border-2.jpg. 
Since certificates are given to many, I used datatool package. I used the particulars of participants in a .csv file namelist-1.csv like this:
degree,Name,Dgn,subject,inst,place
Dr,Abdul Ali,Assistant Professor, E \& I,Pondicherry Engineering College, Pondicherry - 605 014
Mrs,Francesca Joestar,Assistant Professor, ECE,Pondicherry Engineering College, Pondicherry - 605 014
Mr,Chan Ker Mei,Assistant Professor, CSE,Pondicherry Engineering College, Pondicherry - 605 014
Dr,Hikaru Yagami,Assistant Professor, Mechanical Engg.,Pondicherry Engineering College, Pondicherry - 605 014
Dr,Harish Kumar,Professor,Physics,Pondicherry Engineering College, Pondicherry - 605 014
Dr,R. Rajathy,Assistant Professor, EEE,Pondicherry Engineering College, Pondicherry - 605 014
and finally the latex code to generate the certificates is:
\documentclass[16pt]{scrartcl}
\usepackage[a4paper,left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}
\usepackage{pdflscape,setspace,amsmath,amssymb}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{calligra}
\usepackage{tgschola}
\usepackage{fourier-orns}
\usepackage{graphicx}
\usepackage{wallpaper}
\usepackage[normalem]{ulem}
\usepackage{charter}
\usepackage{microtype}
\hyphenpenalty 100000
%=============================
\input Zallman.fd
\newcommand*\initfamily{\usefont{U}{Zallman}{xl}{n}}
%=============================
\usepackage{datatool}
\DTLloaddb{names}{namelist-1.csv}
%=============================
\def\signature#1#2{\parbox[b]{1in}{\smash{#1}\vskip12pt}
\hfill \parbox[t]{2.8in}{\shortstack{\vrule width 2.8in height 0.4pt\\\small#2}}}
\def\sigskip{\vskip0.4in plus 0.1in}
\def\beginskip{\vskip0.5875in plus 0.1in}
%=============================
\definecolor{title}{RGB}{180,0,0}
\definecolor{other}{RGB}{171,0,255}
\definecolor{name}{RGB}{255,0,0}
\definecolor{phd}{RGB}{0,0,240}
%=============================
\begin{document}
\begin{landscape}
\linespread{2}\selectfont
\pagestyle{empty}
\TileWallPaper{1\paperwidth}{1\paperheight}{border-2.jpg}
%=============================
\DTLforeach{names}{
\dg=degree, \name=Name, \dgn=Dgn, \sub=subject, \inst=inst, \place=place}{
%=============================
\noindent
\begin{minipage}[l]{1.5in}
\includegraphics[width=.72\linewidth]{pec_emblem}
\end{minipage}
\hfill
%=============================
\begin{minipage}[c]{6.5in}
{\centering
{\onehalfspacing
{\LARGE\bfseries {\color{other}{{ Pondicherry Engineering College}}}}\\%\initfamily
{\calligra Puducherry} -- {\calligra 605 014\\}
\vskip0.4em
{\large ISTE Short Term Training Program on\\}
{\Large\bfseries\color{phd}{NANO ENGINEERING MATERIALS}}}\\
\par}
\end{minipage}
\hfill
%=============================
\begin{minipage}[r]{1.5in}
\includegraphics[width=.92\linewidth]{istelogo/istelogo-1}
\end{minipage}
\vskip1em
%=============================
\begin{minipage}[l]{1.5in}
\end{minipage}
\hfill
\begin{minipage}[c]{6.5in}
{\centering
{\onehalfspacing
{\Large\bfseries \color{title}{Certificate of Participation}}\par
\vskip0.5em
{\color{pink}\Large\decofourleft\quad{\color{blue}\decoone}\quad\decofourright}
\par}}
\end{minipage}
\hfill
\begin{minipage}[r]{1.5in}
\end{minipage}
\vskip1.8em
{\doublespacing
This is to certify that \uuline{{\large\sffamily\bfseries\color{name}{\dg. \MakeUppercase{\name}}}}, { \dgn}
of {\sub}, {\inst}, {\place},
has successfully participated in the two week Short Term Training Program
on ``\emph{\color{phd}{Nano Engineering Materials}}'' sponsored by ISTE and organized by Department of Physics, Pondicherry Engineering College, Puducherry, from
13$^{\text{th}}$ December to 23$^{\text{rd}}$ December 2010.}
\noindent
%\beginskip
{\singlespacing
\vfil
\begin{minipage}[l]{2.8in}
\sigskip \signature{}{Dr. Harish Kumar \\ Co-ordinator }
\end{minipage}
\hfill
\begin{minipage}[c]{2.8in}
\sigskip \signature{}{Dr. Harish Kumar \\ Co-ordinator }
\end{minipage}
\hfill
\begin{minipage}[r]{2.8in}
\sigskip \signature{}{Dr. Harish Kumar \\ Principal }
\end{minipage}}
%=============================
\pagebreak
}
\end{landscape}
\end{document}
pec_emblem and istelogo-1 are the logos:

And finally the certificate is here: 
This is just for fun and dedicated to Paulo :)
