Here is a list of tools which can do the overlapping procedure. I've used one tool (FLASH) to overlap some MiSeq 2x150 PE reads, and then assembled them using Velvet, and the merged reads produced a "better" assembly than with the paired reads. Enjoy!
PEAR (Paired-End Read Merger) http://sco.h-its.org/exelixis/web/software/pear/doc.html
COPE (Connecting Overlapping Paired End reads) http://sourceforge.net/projects/coperead/
SeqPrep https://github.com/jstjohn/SeqPrep
FLASH (Fast Length Adjustment of Short Reads to Improve Genome Assemblies) http://www.cbcb.umd.edu/software/flash
fastq-join (part of ea-utils) http://code.google.com/p/ea-utils/wiki/FastqJoin
PANDAseq https://github.com/neufeld/pandaseq
mergePairs.py http://code.google.com/p/standardized-velvet-assembly-report/source/browse/trunk/mergePairs.py
I recently used ABySS new program "abyss-mergepairs", source code https://github.com/bcgsc/abyss/blob/master/Align/mergepairs.cc
You can also try USEARCH https://academic.oup.com/bioinformatics/article/31/21/3476/194979
Hope useful.